2021 Corporate Responsibility Report

Corporate Responsibility Report

We aspire to be one of the most sustainable firms in the AEC world, both in the way we design our projects and in how we operate as a responsible business.

Thornton Tomasetti’s big goal is to be the global driver of change and innovation in our industry. Our purpose is to embrace challenges to make lasting contributions. These values define our corporate responsibility approach.

When you struggle to predict with confidence, when longstanding assumptions and practices give way, and when the pace of change accelerates, it’s time to take a new path – to reimagine what you value, what you do and how you work.

Sustainable Development Is Essential to Thornton Tomasetti as an Enduring Organization

29% decrease in average per capita carbon equivalent emissions since 2018 63% 2021 U.S. technical hires from underrepresented groups $2.7M charitable giving since 2013 93% employees who would recommend the firm as a great place to work

The Mosaic leadership board at our New York office on February 24, 2022

Bess Adler/Thornton Tomasetti

Message From the Chairman & Co-CEOs

After disruption comes the inevitable discussion about the “new normal.” But when that discussion draws mainly from past experience, it may constrain a vision of the future. True innovation requires us all – our people, our clients and the end users of our projects – to reimagine a path different from what we anticipated. And it compels us to identify specific areas we need to address if we’re to make lasting contributions along the way. For us, these are community, craft, culture and climate.

Strong communities help us brave uncertainty, so they’re more important than ever. That’s why we’re striving to create a workplace that supports all our people. How and why we work are community-focused too: there is joy in achieving a vision that is accomplished only in collaboration with all stakeholders. Much of our work is literally building communities: designing, analyzing and renewing structures so they meet or exceed requirements for function, sustainability, resilience and aesthetics.

That work – our craft – always starts with people. The pandemic has challenged us to live our values by working harder than ever to build an equitable, inclusive culture. And we’re holding ourselves accountable for our environmental, social and governance goals by publishing Global Reporting Initiative-referenced reporting on our progress.

With a warming world in need of urgent action, climate impact has moved to the forefront of decision-making, for ourselves and our clients. We’re adapting the tools and methods of our craft to reduce carbon emissions and find new ways to secure a livable future for us all.

Sustainable development is essential to Thornton Tomasetti as an enduring organization. We understood this in 2012, when we established our Sustainability practice and our corporate sustainability initiative, and our attention to sustainability is even more relevant today as its importance in our industry rises due to the urgency of

climate change and a pressing need for social equity. Not only do we provide services that contribute to sustainable development, but we face business risks from climate change and other impacts of unsustainable development.

We strive to make lasting contributions to our environment and our communities by promoting and applying creative means of reducing carbon in our projects, committing to achieving carbon-neutral business operations, and influencing policies and practices for sustainability and resilience in our industry and communities. In this reporting period, we’ve made strides toward reducing our operational carbon footprint, and in further developing our capacities in embodied carbon, mass-timber construction, decarbonization, sustainable design and resilience.

Disruption is hard, and it poses real risks. But it also offers unprecedented opportunities for those who seek them. If we can reimagine the possibilities – by being inquisitive, challenging boundaries, advancing ingenuity and applying our craft to solve big problems – we can make the most of this moment. Read on for some of the ways we’re working toward it. We look forward to realizing that future with you.

Michael Squarzini Co-Chief Executive Officer New York

Thomas Scarangello Executive Chairman New York

Co-CEO Peter DiMaggio, Executive Chairman Tom Scarangello and Co-CEO Mike Squarzini

Bess Adler/Thornton Tomasetti

Peter DiMaggio Co-Chief Executive Officer New York

Corporate Responsibility Approach

Thornton Tomasetti’s approach to business management focuses on the three Ps of the triple bottom line, reflecting what we have long recognized: that responsible firms operate and grow in ways that are socially accountable (people), environmentally friendly (planet) and financially sustainable (profit). We aspire to be one of the most sustainable firms in the AEC world, both in the way we design our projects and in how we operate as a responsible business.

Thornton Tomasetti’s big goal is to be the global driver of change and innovation in our industry. Our purpose is that we exist to embrace challenges to make lasting contributions. These values define our corporate responsibility approach.

Strategy

In 2012, we founded a Corporate Responsibility department, led by a corporate responsibility officer who reports to a co-CEO and guided by a steering committee that is representative of our diverse practices and office locations. And although the department was originally established to meet the reporting requirements of the American Institute of Architects’ 2030 Commitment for carbon-neutral buildings, corporate responsibility now spans all our departments and disciplines.

To manage the firm’s positive and negative impacts on the economy, the environment and people, every five years the Corporate Responsibility department works with our Corporate Responsibility Steering Committee to update our short-, medium- and longterm strategies and reexamine our goals and measurable targets for achieving this vision (see "Corporate Responsibility Goals " and "Corporate Responsibility Targets " ).

By driving innovation and embracing challenges – seeing opportunity where others may focus on risk – we’ll ensure our firm’s own sustainable development and contribute to a more sustainable building industry. And in accordance with our core ideology, we’ll bolster our long-term growth and reduce business risks by making meaningful investments in people and the planet, recognizing that these investments drive innovation and lead to greater long-term value. Our approach will influence our clients and suppliers as we continue to build relationships with trusted partners who share our commitment.

Corporate Responsibility Goals

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Our seven corporate responsibility goals guide our corporate responsibility approach. Every five years, we revisit these goals during a strategic planning process that mirrors the firm-wide five-year planning for our practices and offices.

of employees feel they have service opportunities

increase in service hours from previous year 30% employees engaged in Thornton Tomasetti Gives Back 90% U.S. offices engaged in ACE Mentor Program

&

Demonstrate Positive Environmental & Social Impact Across All Practices

Designing for a better world is the future of our industry. To be the global driver of change and innovation in our industry, we must demonstrate that design professionals can solve the most challenging social and environmental problems through our work. We have the expertise and cross-practice opportunities to be a leader in this area. This path will result in an enduring organization.

Lead the Industry in the Reduction of Embodied Carbon in Structures

Our best opportunity to demonstrate positive environmental and social impact lies in areas where we can make the greatest contribution, based on our knowledge and talent, and where we can apply our ingenuity. Embodied carbon is a rapidly emerging area in which we, as a multipractice firm with a strong grounding in structural engineering and expertise in sustainability, can be a driver and hold a unique position in the AEC industry.

Achieve Carbon-Neutral Business Operations by 2030

Through our Sustainability practice and our adoption of the Architecture 2030 Challenge, Thornton Tomasetti is an active participant in reducing emissions that contribute to climate change. We engage our employees in the global effort to mitigate and adapt to climate change by practicing what we preach through our internal policies and behaviors.

Promote an Inclusive

& Diverse Community

Everyone at Thornton Tomasetti is empowered to change our industry. We know diversity drives innovation, so we will set and achieve targeted data-driven goals to increase inclusion and diversity among our staff, leaders, owners and board of directors. We will cultivate a welcoming and rewarding environment where everyone can achieve their full potential throughout their career journey here. We will increase our investment in continuous learning to expand and nurture our staff and future leaders. And we will support opportunities for everyone at our firm to give back to their communities.

Support a Healthy & Lifestyle-Friendly Workplace

Caring about our employees is part of our culture of respect. We want a healthy and lifestyle-friendly workplace because we care about our people, but also because we want to attract and retain the best talent and reduce healthcare costs.

Support Our Employees’ Passion for Community Service

Our employees have unique capabilities that can add value to their communities, and they want to share their skills with others in need. Community service allows us to challenge people to grow and build relationships in the communities where we live and work.

Accelerate Leadership Development & Professional Growth Opportunities

Our firm encourages professional development at all levels. We are committed to creating a pipeline of world-class and diverse leaders. Our growth opportunities increase employee retention and lead to better work outcomes, innovation and leadership in the industry.

Corporate Responsibility Goals

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Our goals help illuminate the environmental, social and governance (ESG) topics that are most material to our business and of interest to our stakeholders. Early in 2022, we conducted a materiality assessment that identified topics for measurement and reporting. This assessment built on our prior years of sustainability reporting and our corporate responsibility strategic planning.

NSTRATEPOSITIVE ENV I RONMENTAL&SOCIAL

We examined these questions: What is the impact to our business, and what is important to our stakeholders? Our stakeholders include our employees and potential hires; owners, clients and partners; potential clients and partners; our suppliers; and our communities. We approached our materiality assessment with the following assumptions:

• After almost a decade of corporate responsibility reporting, we had identified social and environmental topics important to our business. A materiality assessment could help uncover impact areas we had not explored.

• We could learn about what was important to our stakeholders by researching the material topics that rose to the top for clients and partners within our sector.

• Thornton Tomasetti is a private service company in a nonmanufacturing and nonextractive industry. Therefore, topics that are significant to large public companies may not be immediately significant to our firm.

We started the process by outlining the Global Reporting Initiative (GRI) material topics and the legacy topics we had been measuring and chronicling through our annual sustainability reports. Since no GRI sector standard exists for engineering, we didn’t include any sector standard topics. Then we reviewed the GRI reports of client and partner firms in our industry and identified the material topics they value. After acquiring this information, we held dialogue sessions with our department leaders, executive committee and corporate responsibility steering committee. Co-CEO Peter DiMaggio approved the final list of significant topics for reporting.

Three tiers of material topics emerged from these sessions:

• Tier 1 topics are of highest materiality to Thornton Tomasetti and are covered in this 2021 corporate responsibility report.

• Tier 2 topics are of importance to our stakeholders and to the engineering sector (for example, occupational health and safety) but currently are not outstanding risk factors or major impact areas for our firm. We may consider including some or all of these topics in 2022 reporting.

• Tier 3 topics do not apply to our business model or sector (for example, freedom of association).

Our Tier 1 topics include economic performance, energy, emissions, employment, training and education, diversity and equal opportunity, and nondiscrimination. In addition to these topics listed by GRI, we include our legacy topics of community service and employee wellness.

When evaluating the impacts of these material areas, we considered both short- and long-term impacts and any areas of grievances. We recognize that our Tier 2 topics may not be immediately important, yet they could become more material to our business and sector in the long-term. In selecting material topics, we considered that Thornton Tomasetti often provides a service to a multidisciplinary design team as a subcontractor to another firm and therefore may not have direct influence on suppliers to our projects.

We have selected nine material topics (see next page).

Corporate Responsibility Goals

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Thornton Tomasetti Material Topics

This Year's Targets

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To gauge progress toward our seven corporate responsibility goals, we create measurable short- and longer-term targets. The short-term targets for 2021 that we reported in last year’s corporate responsibility report supported our overall corporate responsibility goals in three areas:

100% of Our Structural Engineers Will Understand How to Deploy Embodied-Carbon Reduction Strategies on Projects

Thornton Tomasetti is an inaugural member of the Structural Engineers 2050 Commitment (SE 2050) launched in 2020, which calls on engineers to achieve netzero embodied carbon in their structural projects by 2050. Our SE 2050 EmbodiedCarbon Action Plan (ECAP) states, “By the end of 2022, 100 percent of our structural engineers will know what embodied-carbon capabilities we have and will understand how to deliver them to clients and deploy them on their projects.”

To understand our progress toward this target, we surveyed our structural engineers in October 2021. We found that 46 percent of them felt they had a moderate understanding of what embodied carbon is and how it relates to their work – and were confident they could clearly explain it to someone else. About half were aware of the services we offer to clients to reduce embodied carbon in projects. What did we learn? While we’ve made great strides toward improved understanding, we need to continue educating our structural engineers about embodied-carbon reduction methods and sharing information across the firm on embodied-carbon projects.

Through our 120-member embodied-carbon community of practice (CoP), we’re working to educate our people and ensure that our engineers have access to the methods and tools they need to do the work of embodied-carbon reduction. In 2021, we made progress toward our target of 100 percent of our structural engineers understanding how to deploy embodied-carbon reduction strategies on projects in the following ways:

• Developing embodied-carbon specifications to include in our design standards

• Hosting an internal embodied-carbon summit

• Offering continuing education through a regular embodied-carbon seminar series

• Writing an embodied-carbon assessments manual for our technical staff

• Building an embodied-carbon resource library on our company-wide intranet

• Launching our first SE 2050 submission – our Embodied-Carbon Action Plan

In 2022, we identified embodied carbon as a priority for Thornton Tomasetti practices. In addition to our ongoing efforts through the CoP, we’ve increased our investment in direct training programs for technical staff. We anticipate that by the end of the year, 100 percent of our structural engineers will be fully aware of our embodied-carbon capabilities. The best source of knowledge for delivery of these services is practice –working with our clients and partners, we see growing opportunities for our engineers to contribute to projects with carbon-reduction goals.

Lead the industry in embodied-carbon reduction.

46%

of our structural engineers understand how embodied-carbon strategies relate to their work.

Promote an inclusive & diverse community.

over 75% of employees perceive a positive impact from ED&I.

Support our employees’ passion for community service.

71% of employees feel they can engage in service opportunities.

75% of Employees Will Be Actively Involved in Our Equity, Diversity & Inclusion Initiative

In the last few years, we’ve seen firm-wide engagement in our Equity, Diversity and Inclusion (ED&I) initiative, with the highest participation recorded in 2020: 98 percent of the 624 survey participants said they were involved in ED&I activities. We had established a lower target (75 percent) for 2021 because 2020 had been atypical due to a sharp increase in remote work, programs being administered virtually, and heightened awareness of racial and social justice issues resulting from high-profile news events. Because of this, we expected 2021 to be more “normal” and were pleased that our high participation rate continued, with 80 percent out of 1,108 survey participants noting their involvement.

Survey respondents said that they had been involved in one or several 2021 ED&I activities, which included a three-part antiracism course paired with discussion groups; celebrations of historic events and holidays, including Martin Luther King Jr. Day; local office ED&I activities; and participation in our employee network groups, Mosaic (multicultural) Spectrum (LGBTQIA+) and Women@TT Our 2021 employee survey indicated that almost all (91 percent) our employees are familiar with the ED&I initiative and 81 percent believe that their managers promote the initiative. Since awareness and support from managers pave the path for participation, we anticipate that participation in ED&I will remain high.

This Year's Targets

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Achieve carbon-neutral business operations by 2030.

Achieve a carbon footprint below 3.48 MT CO 2 e per person.

2022 2022 2022 2022

Accelerate leadership development & professional growth. Offer mentoring to all employees.

100% of Employees Will Feel They Are Given Opportunities to Offer Their Skills for Community Service

Our Thornton Tomasetti Gives Back program offers employees opportunities during the workday to volunteer their time and skills to aid people in need. A recent survey showed that 71 percent of our employees feel they are given opportunities to offer their skills for community service. But while this is a majority of our staff, it still doesn’t meet our target of 100 percent. Not all employees are able to take advantage of this opportunity for reasons that include not being aware of the program offerings or lack of time. Some survey participants are seasonal staff (such as interns) and are not eligible to be paid for community service. Decreased community service hours during the pandemic may also have resulted in reduced awareness of the program.

Despite the challenges posed by COVID-19, we still aspire for all eligible employees to recognize and embrace opportunities for community service. Here’s how we’re working to achieve 100 percent participation:

• Our local corporate responsibility champions are encouraged to plan two community service activities each year for their offices, and this action is prioritized for 2022.

• Our corporate responsibility grants program covers some of the costs of community service events, including sponsorship fees, reducing barriers to entry.

• As we honor national and global events like Earth Day, International Women’s Day and Martin Luther King Day of Service, we find related opportunities for community service.

• Now that we're back in our offices most of the time, more employees can engage with their co-workers in group activities, and avenues for community service, which were closed earlier in the pandemic, are now open.

Promote an inclusive & diverse community. Ensure 100% of employees are familiar with our equity, diversity & inclusion initiative.

Looking to the year ahead, we're working to achieve measurable short-term progress toward our corporate responsibility goals in these three areas (and more!) by the end of 2022.

Progress Report: Financial Vitality

Each year, we report on several indicators (in U.S. dollars) that show progress toward achieving our financial-vitality goals. The trends this reveals can show how our corporate responsibility programs contribute to our vitality over time.

GOOD WORK Designing for a Better World Is the Future of Our Industry

OUR GOOD WORK Building Community Showcase

J. Tamaro P.E., LEED AP

Principal

The 26-acre site includes offices, a hotel, a performing arts center, public green spaces, sculpture parks, a grocery store, bars and restaurants.

Project:

Capital One Center, Tysons, Virginia

Our Solutions:

Commercial & Residential , Construction Engineering , Structural Design

A Vibrant Urban Center for a Suburban Neighborhood

As Metro, the subway system serving the Washington, D.C., region, expanded westward toward Dulles Airport, Capital One made big plans for a new transit-oriented development. On a 26-acre site in Tysons, Virginia, that was once largely cut off by highways from the surrounding apartment and condominium complexes, Capital One Center now sports offices, a hotel, a performing arts center, public green spaces, sculpture parks, a grocery store, bars and restaurants.

Our engineers have provided structural design for several of the projects in the development:

• Capital One Tower, a 1.7-million-square-foot office building designed by HKS Architects

• Capital One Hall, a high-end performance space and community cornerstone, which opened in 2021. Designed by HGA it houses a 1,600-seat main theater, a 225-seat black-box theater and a large atrium. A rooftop park features a 230-seat amphitheater, a sculpture garden and a biergarten, all set amid lush landscaping.

The 23-story west tower and the 30-story east tower of the newest office building (far left) are tied structurally by 10 bridges – some steel, some concrete – that span the 1.6-million-square-foot building’s atrium.

Michael Cropper/Thornton Tomasetti

• The performing arts center shares a parking garage and loading dock with its neighbor, a 1.2-million-square-foot building that comprises a hotel and a grocery store. This building was designed by a different team, led by Gensler so coordinating the common below-grade structure was critical. Having both structural engineering teams in the same office simplified collaboration.

• Another office tower that’s really two buildings connected by an atrium and tied together by a series of bridges that span the open space in between. This efficient structural solution meant that a large expansion joint between the two main structures – complicated to design and costly to build and maintain –wasn’t necessary. We were also hired by the steel fabricator to perform erection engineering for the project, which will be completed in 2022.

Our work at the site continues, with design underway on two more projects from the development’s master plan, which includes residential buildings and more office and hotel space.

Mark

OUR GOOD WORK Decarbonization Showcase

Fighting climate change is a battle we’re waging on many fronts –from energy generation, storage and use to design and operation of the built environment. Decarbonizing heavy industry , especially the power sector – which produces about a quarter of human-generated greenhouse gases – is one focus of our work on decarbonization and non-carbon energy technologies.

Pawel Woelke Ph.D., P.E. Principal & Aberdeen, Bristol, Belfast & Warrington Co-Office Director Warrington

Thornton Tomasetti

As utilities replace conventional power plants with renewables or upgrade them to clean energy options, we help by performing advanced modeling to determine the best and safest ways to demolish outdated facilities. Sometimes deconstruction is necessary for safety; at other times, a designed implosion is optimal. We’re modeling the demolition of two coal-fired units in Asheville, North Carolina, to make way for solar power generation and energy storage facilities.

Long-term storage of spent nuclear fuel and waste is an ongoing global challenge. We’re developing new technologies for better waste management. For one client in the U.K., we’re applying skills in thermal, chemical and structural mechanics – honed by serving military clients – to develop computational models to verify waste container safety (right). The models will allow the client to safely certify multiple design options without having to test every design iteration, saving time and expense. Ultimately, our assessment will help optimize container design, manufacturing and arrangement.

We’re also modeling spent-fuel storage options for micromodular nuclear reactors. These reactors – typically rated at 10 to 500 megawatts – are much smaller than conventional reactors and often replace coal- or diesel-fired plants that are far from any electricity grid. Thanks to their modular construction, they can be built quickly and for about a quarter of the cost of conventional reactors. Their different fuel design is one factor that makes them safer to operate, but their spent fuel still requires a safe storage option.

We’re also working with developers of fusion reactors in the U.S. and U.K., building computer simulations to assess the production rate of tritium, which fuels the fusion reaction. These models are advancing the safety and efficiency of real-time tritium production and will help optimize the design of fusion reactors. And we’re providing a wide range of engineering services for fusion-power pioneer Commonwealth Fusion Systems.

Renderings based on results from our predictive modeling to assess the safety and integrity of nuclear waste containers subjected to extreme loading. Our model predicted that the housing would not be breached, despite damage to the interior container.

OUR GOOD WORK Embodied Carbon Showcase

Because the building sector generates up to 40 percent of global carbon-dioxide emissions, our role in combating climate change goes beyond sustainability consulting: we calculate and help reduce embodied carbon – the carbon footprint of building materials – in the buildings we design.

—

Scott Schneider, Principal, Thornton Tomasetti

Spurred by the Carbon Leadership Forum’s (CLF) Structural Engineers 2050 Challenge, more companies are recognizing the importance of minimizing embodied carbon (EC). Following years of carbon-related R&D, we worked with CLF and others to conceive and develop the challenge, which calls on structural engineers to “understand, reduce and ultimately eliminate embodied carbon in their projects by 2050.”

Our CORE studio developed software for the database used by the Structural Engineering Institute to track and report on EC for its SE 2050 Commitment program, which it created in response to the challenge. In 2021, as part of that commitment, we formalized an Embodied Carbon Action Plan (ECAP), laying out our EC targets in four areas: education, reporting, reduction strategies and advocacy.

Much of our focus over the past year has been on ensuring that everyone in the firm understands why embodied carbon is important, how to measure and address it, and how to discuss it with clients. Our EC community of practice hosted a firm-wide embodied-carbon summit in April 2021. We also formulated new concrete and steel specifications for EC and introduced a monthly “EC Shorts” program, in which an employee talks briefly to colleagues about work, strategies, materials or applications related to EC reduction.

P.E., LEED AP Principal & Structural Engineering Practice Co-Leader New York

Our CORE studio which has created applications – like Beacon – that track embodied carbon in building projects, is developing new tools that will perform a variety of tasks, including design for composite and concrete beams; steel and concrete columns; and timber bays, beams and columns. These tools will automatically update EC estimates when a user alters any component of a model.

Scott Schneider

A structural machine-learning design and embodied-carbon takeoff for a tower created in Swarm Asterisk. Thornton Tomasetti

OUR GOOD WORK

Life-Sciences Showcase

Debus Ph.D.

Peterson Ph.D.

As the medical device industry moves toward a digital ecosystem, in silico trials, alone and in combination with traditional trials, are becoming a reality.

In Silico Hybrid Trials: Life on the Leading Edge

Our life-sciences team is developing technology to create virtual cohorts using parametric anatomy modeling. We develop models for materials like Nitinol and tissue and use a wide range of commercial tools to make in silico trials a practical tool for medical device manufacturers. We have the expertise and mastery of the tools needed to produce these digital solutions – tools that perform mechanistic, multiphysics simulation and AI/machine learning.

When you’re buying a T-shirt, your options are often limited: large, medium or small. But what if you need a life-saving stent or valve implanted in your heart? The natural variations in the human body mean that our anatomy doesn’t often fit into predetermined categories of shape and size.

Enter in silico testing. In silico is a technical term for an analysis that takes place in a computer model or simulation rather than in living patients. In silico trials enable medical professionals to simulate each person’s unique anatomy, then create and test devices virtually and predict their effectiveness – without ever cutting into a patient.

The in silico method allows tests to be performed on hundreds of individuals simultaneously, expediting data collection. It also makes it possible to create a wide range of devices that fit patients from specific age, race or gender groups that tend to share anatomical traits – or even to custom-build devices for a specific person.

Working with Synopsys, Duke University and Johns Hopkins University, we’re using in silico testing to predict the behavior of implanted heart-valve frames. Using 4D MRI data, we conducted finite element analysis to simulate the motion of an aortic-valve frame in five patients. The models can predict contact pressure, leakage, movement of the frame over time, and distribution of stress before and after implantation.

This technology improves device design, aids in identifying disease-related design issues, minimizes failures and helps doctors make more-informed decisions regarding the health of each of their patients.

Ashley

Kristian

At the Heart of Healthcare Research

Thornton Tomasetti

OUR GOOD WORK Mass-Timber Showcase

An elegant, environmentally responsible and subtle architectural statement on a UNESCO World Heritage site.

Scott Lomax CEng, MICE

Principal

Project: Atelier Sérgio Rebelo, Tabuaço, Portugal

Our Solutions:

Cultural & Community, Hospitality & Gaming , Sustainability, Structural Design

A Meeting of Past & Future

Wood is one of the world’s oldest building materials, but now – in the form of mass timber – it’s also a sustainable material for the future. A new winery and hotel in Portugal’s historic Alto Douro wine region is bringing wood back to the present.

We’re providing structural design and sustainability services for a new hospitality complex, which is being built on a UNESCO World Heritage site The design by Atelier Sérgio Rebelo harmonizes with the landscape, a valley along the Douro River, where terraced vineyards produce the region’s famed Port wines. The 9,700-square-foot winery features sinuous lines that mirror the curving terraces, while the 34,500-squarefoot hotel is divided into several smaller buildings around a courtyard – an arrangement that echoes the region’s age-old monasteries.

The use of natural materials, including exposed heavy timber columns, rafters and trusses, further integrates the complex into the hillside. Our team is applying experience in a variety of mass-timber applications – including Ascent , the tallest mass-timber building in the world – to develop an elegant and efficient structural design for the project.

These timber elements also make the structures more sustainable. Our structural engineers are collaborating with our sustainability experts to create an environmentally friendly development. Selection of materials and construction systems was guided by a close study of local architecture and a desire to use regionally sourced natural materials.

We also studied the local climate to engineer energy-saving solutions that will help reach the owner’s goal of net-zero emissions from annual operations at the complex. We took advantage of the region’s superb weather for natural ventilation, dramatic daylighting and solar energy generation, further integrating the complex into its surroundings. Any additional heating and cooling needs will be met by a geothermal system.

Project Awards

World Architecture Festival Future Projects – Leisure-Led Development and Special Prize for Visualisation, 2021

Architizer, A+ Award – Unbuilt Hospitality, 2021

Quinta De Santo António Hotel and Winery, Tabuaço, Portugal.

Courtesy Atelier Sérgio Rebelo

OUR GOOD WORK

Social Equity Showcase

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Many publicly funded projects set levels of participation for minority- and women-owned business entities (MWBEs), so often there are two consultants engaged for each design discipline. These requirements are sometimes seen as irksome by larger firms, and scope divisions can be unfair, with the MWBE firm given less interesting pieces of the work. And with two firms instead of one, coordination can suffer.

Lisa Chong

Vice President Washington, D.C.

Mark J. Tamaro P.E., LEED AP

Managing Principal & Mid-Atlantic South Region Leader Washington, D.C.

At its best, though, collaboration between a larger firm and an MWBE can benefit both parties, as well as projects and their stakeholders. Our Washington, D.C., office has partnered with small, woman-owned structural firm A+F Engineers on more than 12 projects over 17 years. Representatives of both recently sat down to discuss their experience together.

You have a long history together. How did that start?

Mark remember the first meeting. It was a really fast schedule, so there was concern whether or not each of the parties was going to be able to do their piece. But right off the bat, it was comfortable. We sat down with some 11-by-17 sheets and green and yellow highlighters, and that’s how we figured out who was going to do what.

Dimitrios We said, “Well, you do this, and we’ll do that,” in a way that made sense, and when we were done, it was proportionally correct to our fees. It was going so well, we even went down to the little details, like who does the scoreboard and the flagpole.

Mark And we never had to talk about it again. It was pretty amazing. Neither of us was going to let the other down.

What makes the relationship work so well?

Dimitrios It clicked from the beginning. After the first discussions with Mark, we knew we were on the same page technically and we felt we could trust each other.

Mark We’ve never had an argument over fees.

Dimitrios And because we had developed this trust and this relationship, we’ve never had a gap between our scopes.

Mark One of the signs of success is when the client doesn’t know which firm you’re from.

Lisa Exactly. It takes extra communication to make that happen, but it pays off.

Myranda To succeed in that, you also need to have the same technical standards, business standards and philosophy. Thornton Tomasetti always fought for fair fees for both firms. Technology is important too. When we started A+F, we invested in compatible software, so we could work easily together.

Dimitrios How the scope is split is also important. Sometimes MWBE firms are given the foundations and that’s it. But we’ve gone back and forth. On one project, we did the superstructure and you did the below-grade work. But on the next project, we switched.

What’s the most interesting scope split you’ve done?

Lisa The Assembly in Pittsburgh. A+F owned the roof, and we owned the walls, so it was very interesting.

Dimitrios Right.

Lisa It’s a really cool building. It has a massive open space where trains could drive in. The first time I went on-site, though, that part was in bad shape, and thought, “How is this thing still standing?” That was when they asked if we could bring in any smallbusiness participation. It seemed like an easy thing to carve off, but we knew it would be incredibly complicated.

Dimitrios The scope was all integrated.

Lisa And when A+F did the peer review for the remainder of the building, it felt like an internal quality-control review. It was not adversarial at all.

A+F Engineers Principals Dimitrios Frantzis and Myrofora “Myranda” Anastasi © Johnny Shryock

Social Equity Showcase

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As a young company, the partnership helped us win large, interesting projects that we couldn't get by ourselves. This was very important. And now it helps us keep our employees, because they get to do technically challenging work.

In 1915, this Ford Model T assembly plant in Pittsburgh, Pennsylvania, was at the cutting edge of industry. Now it’s been transformed into The Assembly, a center for life-science research and innovation.

Courtesy ZGF

All projects have bumps in the road. How do you deal with that?

Dimitrios Our relationship got tested many times, and we proved that we are there for each other.

Myranda And defending each other, not trying to push the blame to the other party.

Mark A lot of people like to be able to say, “Oh, that’s their problem.” We’ve been so intertwined, because many of the projects have been single buildings, that we couldn’t do that, even if we wanted to. We just needed to work together and solve the problem.

We go after complex buildings, and that’s another thing we have in common. We both like the technical challenges. That’s what makes it exciting.

How does this long-term relationship benefit both firms?

Myranda As a young company, the partnership helped us win large, interesting projects that we couldn’t get by ourselves. That was very important. And now it helps us keep our employees, because they get to do technically challenging work.

Dimitrios It also kept us going. There were periods when all we had in the office were projects we were working on together. And we built a strong portfolio, which helps when we go after new projects, alone or as a team.

Mark For us, the most significant benefit is the incredible confidence we have in the team, so we can be aggressive in going after complex projects and good fees. You don’t get that with one-off relationships. That portfolio we have together helps us win projects. We actively look for projects to work on together, knowing it’ll strengthen those benefits.

Myranda We’ve also gone to our clients and said, “If you want a national firm to team with us, this is the one.” We always feel comfortable doing this.

Any advice for how others can build similar relationships?

Mark When you find a good partner, latch onto them and don’t let go. Then you build on that, because you build momentum. Every project you do together increases that bond and that strength.

Lisa It makes you more marketable, because people don’t want you jammed together for just one project. They want to see that relationship, that you’ve worked successfully in the past.

Dimitrios Yes. We’ve had 17 exciting years, both technically and personally. We have cemented friendships, and we love that, and we’re looking forward to more to come.

OUR GOOD WORK Sustainability Showcase

Stout AIA, LEED Fellow, WELL AP Vice President San Francisco

Merck's new West Coast headquarters, one of the first laboratory buildings in the world to be WELL Certified, is as green as it is healthy.

Project:

Merck Research Laboratory Headquarters , South San Francisco, California

Our Solutions: Laboratory & Research , S ustainability

Biopharmaceutical company Merck has a new West Coast headquarters that is as green as it is healthy. In addition to holding LEED Gold ratings for core-and-shell and commercial interiors, the 308,000-square-foot building in South San Francisco also earned LEED Zero Energy and Zero Carbon certifications. And it’s one of the first laboratory buildings in the world to be WELL Certified.

We provided sustainability consulting for the multidisciplinary research facility, designed by Jacobs, which houses some 300 scientists and support staff. Its nine-story tower is connected to a three-story amenities building, which features an auditorium, fitness center, café and parking garage. To conserve natural ecosystems and promote user well-being, nearly a quarter of the seven-acre site is devoted to green space.

Pursuing LEED and WELL certifications together on a project of this scale was a rare challenge: while some crossover exists between them, it required careful planning to meet the criteria for both systems. Since this was our first time incorporating the WELL Building Standard into a laboratory building, creative thinking and close coordination with the International WELL Building Institute (IWBI) provided valuable insights into how best to apply the standard to this complex project type.

Here are some of the strategies we applied that satisfy both LEED Zero and WELL criteria:

• Construction materials meet stringent volatile organic compound (VOC) content and emissions standards.

• Minimum efficiency reporting value (MERV) 13 media filters in the ventilation system support occupant health.

• Mechanical systems are sized to accommodate carbon filters that remove VOCs and large particles.

• Use of tobacco products is prohibited in and around the property, including terraces and outdoor areas.

Research and development buildings are typically energy-intensive – and this one offered opportunities for significant energy reduction. Simulations developed early in the project’s design helped the team determine the best methods for reducing energy consumption. These included strategic building orientation, mechanical systems design and glazing selection. And our energy modeling showed that the addition of a photovoltaic array atop the parking structure could generate about 4 percent of the energy needed by the facility.

We achieved additional energy and water savings by recommending energy-efficient LED lighting and water-conserving plumbing fixtures. And a custom measurement and verification plan ensures that building management can continuously track electricity usage and address discrepancies between actual and targeted energy savings.

Joel

Merck Research Laboratory Headquarters, South San Francisco, California. Thornton Tomasetti

OUR

WORK Progress Report: Our Good Work

Each year, we track several indicators that show progress toward our goals for socially responsible and sustainable projects.

We calculate average per-project cost savings from our sustainability consulting services using energy savings and an average fuel-unit price, so rising energy savings yield greater cost savings for our clients year after year. The significant increase in cost savings in 2021 can be attributed to the same factors that influenced emissions reductions.

Engineering News-Record’s annual Top 100 Green Buildings Design Firms ranking is based on the year’s design or construction revenue from projects that have been registered or certified by a third-party organization that sets standards for measuring the environmental impact of buildings.

Average embodied carbon per square foot represents the global warming potential of the structural framing materials used in our major projects. In 2019, we introduced our Beacon tool to quantify the CO 2 e emissions from structural elements and now use it for our annual assessment. In 2021, we paused our annual embodied-carbon count after joining the Structural Engineers 2050 Commitment (SE 2050) to develop our SE 2050 embodied-carbon action plan, which is the first step in meeting the commitment. In line with SE 2050, we will report on 30 projects for 2022.

Our carbon dioxide equivalent (CO 2 e) reduction metric tracks the impact of sustainability improvements – like energy-efficiency measures and other strategies for reducing operating energy – that result from our sustainability consulting work. This total is the sum of individual project savings derived from energy modeling. Our goal is to have a significant impact on CO 2 e emissions. The large increase in emissions savings in 2021 can be attributed to a 260 percent rise in average project size and a surge in the number of building projects pursuing zero net energy and going all-electric in utility regions with greener grids.

This chart includes all our sustainability consulting projects that are registered or certified through a green-building program , such as LEED or Living Building Challenge. Each cumulative total includes all projects from previous years (note that this chart does not include Thornton Tomasetti projects for which we didn’t provide sustainability consulting services). Since the launch of our Sustainability practice nine years ago, the number of green-building registered and certified projects has grown by 91 percent.

Our R&D spending includes staffing and other support for CORE studio our virtual incubator of ideas, as well as semiannual innovation tournaments, which identify promising ideas from employees across the firm. These ideas then receive funding and support for further development. Since 2013, we’ve invested $11.7 million, with increases every year. Why? To help achieve our long-term goal of being the global driver of change and innovation in our industry.

Thornton Tomasetti's Fort Lauderdale office, designed by Gensler.

SUSTAINABLE OPERATIONS

Emissions Update

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We’re committed to achieving carbon-neutral business operations by 2030. We established this goal in 2012, and since then have been reaching our targets by reducing energy use wherever possible and offsetting emissions for business-critical activities.

Although our largest impacts on climate change are from our services, we’re aware that the carbon footprint of our operations is significant as well. Tomasetti is a global firm with 46 offices. Our most recent carbon footprint analysis (2021) shows an operations footprint of 3,547 metric tons (MT) of CO 2 e before offsets – equivalent to the annual footprint of 74 average U.S. households ( Source: Center for Sustainable Systems ). So we’ve set reduction targets to help us reach climate neutrality:

• 10 percent reduction in per capita emissions each year

• 50 percent reduction in our per capita emissions from 2018 levels by 2030

• We are currently setting a target reduction for absolute emissions. Our reduction targets have previously been set for per capita emissions

We make progress toward these targets by:

• Designing high-performance offices Eleven of our office fit-outs have been LEED Gold or Platinum (or equivalent program) certified, and we apply our sustainable fit-out policy to all major office moves and renovations, so our energy-performance goals exceed minimum standards. In our existing offices, our green champions work to reduce energy use according to our sustainable-office guidelines.

• Using renewable energy. We’ve met our green-energy purchasing percentage targets each year since 2015 as a member of the U.S. Environmental Protection Agency’s Green Power Partnership, and we continue to purchase renewable energy certificates (RECs) for 25 percent or more of our U.S. electricity use.

• Flying less, offsetting the rest. The pandemic required us to be more agile about building relationships without traveling. We have the tools that enable remote meetings, and we’re asking the questions that minimize unnecessary travel. Every year since 2014, we’ve offset all our air travel through Carbonfund.org which supports renewable energy and efficiency projects.

• Enabling flexible work. In 2017, we established a global flexibility policy, offering work options that reduce commuting emissions while maintaining our collaborative culture. At the height of the COVID-19 pandemic, remote work became the norm.

Since 2018, we’ve achieved a 29 percent reduction in our average per capita emissions and are making good progress toward our reduction targets for carbon neutrality in 2030. Our challenge now is to maintain the low emissions levels we’ve seen throughout the pandemic as people return to their offices and engage in more business-related travel.

Since 2014, we have offset 8,281 metric tons of CO 2 e of Scope 3 emissions through third-party certified and validated renewable energy and energy-efficiency projects.

In the reporting period, we’ve offset 531 metric tons of CO 2 e and purchased Green-e ® Climate certified RECs for 318.59 metric tons of Scope 2 CO 2 e emissions. We account for business travel emissions through ticket invoices and a regression model formula that estimates emissions based on the relationship between ticket purchases and emissions. We account for electricity emissions through direct electricity bills and, when precise electricity use data for our offices is not available, records from the buildings in which we lease space.

In 2021, the pandemic continued to affect our work in ways that lowered our carbon footprint. Our business travel emissions remained low throughout the first two years.

At 531 metric tons of CO 2 e, our 2021 emissions from air and train travel were about one-third less than those of 2019.

We calculate our carbon footprint by examining electricity use and heating (Scope 2) and business travel, employee commuting, and office waste (Scope 3). Our last complete carbon-footprint analysis, conducted biennially, indicated that in 2020 we met our reduction target of 10 percent per capita from the previous year (before offsets), achieving a 2020 per capita carbon footprint of 2.73 metric tons of CO 2 e. Carbon offsets brought that down to 2.33 metric tons, with a total reduction of 478 metric tons of CO 2 e achieved through carbon offsets and renewable energy certificates.

Methodology

Our carbon-footprint analysis uses 2018 as the base year for calculations. Although we began calculating our operations carbon footprint in 2012, we readjusted our baseline year following a 2016 merger that increased our employee numbers by 25 percent. We conduct a biennial analysis for even-numbered years, and 2018 was our first year of analysis after the merger. That year, our firm-wide carbon footprint was 4,757 metric tons of CO 2 e without offsets. With offsets, it was 3,401 metric tons. Our organizationspecific metric for the intensity ratio is number of employees. In 2018, our intensity ratio showed 4.07 metric tons of CO 2 e per person, without offsets. With offsets, it showed 2.91 metric tons of CO 2 e per person.

Our location-based method uses calculations that draw from the U.S. Environmental Protection Agency’s emission factors for U.S. regions. Emission factors for our offices outside the United States are obtained through each country’s environmental agencies. We purchase carbon offsets for all air and train business travel emissions (CO 2 e) and renewable energy certificates (RECs) for a minimum of 25 percent of the CO 2 e emissions from electricity used by our leased offices.

SUSTAINABLE OPERATIONS

Responsible Purchasing Update

Because our role in projects is often limited to design and consulting, our direct procurement activities are typically limited to the purchase of office supplies. In cases where we do hire subconsultants or specify materials for projects, we follow our Ethical Sourcing Policy, which helps ensure that the products we procure are sourced in a responsible and sustainable manner and that individuals involved in their manufacture are working in a safe and fair environment.

Our contracting process promotes social equity by encouraging the hiring of small businesses owned by socially and economically disadvantaged people or employing firms that have demonstrated a clear mission of promoting social equity.

In line with our environmental statement – to apply creative means of reducing carbon in our projects – we are guided by our embodied-carbon specifications for concrete and steel, developed in 2021, when sourcing building materials so that our structural engineering projects use materials or adjustments to materials that are less carbon intensive than standard options. We also aim to avoid the use of toxic materials on the Living Building Challenge Red List

Following our sustainable office guidelines, we give preference to office supplies with high recycled content and low toxicity. In the United States, we purchase 60 percent of our office supplies through Staples, which classifies eco-products as either “basic” or “advanced.” Those categorized as "basic" include eco-features that are more common among products in the industry, such as containing less than 30 percent postconsumer content. "Advanced" products boast leading environmental features, such as a certification under a leading standard established by third-party programs like Energy Star, fair trade and Cradle to Cradle.

In 2021, 26 percent of the office supplies we purchased from Staples met the criteria for “eco-products.” This is lower than our pre-pandemic average of nearly 50 percent. Why this reduction? We bought fewer office supplies in 2021, and many were from vendors other than Staples. Items purchased from Staples were primarily food ware, breakroom supplies, paper and ink. At 59 percent of expenditures on paper products, our eco-spend on paper was higher than those for all other products. Paper-use reduction is addressed in our sustainable operations guidelines, which recommend using 100 percent post-consumer recycled paper, distributing documents electronically whenever possible, and printing on two sides when hard copies are needed.

This declining level of office-supply purchasing is a positive trend, since we reduce our carbon footprint when we consume less. That’s why our sustainable operations guidelines encourage our offices to seek additional ways to reduce supplies and limit resource use. For example, consolidating orders lowers delivery-related transportation emissions and reduces packaging materials used by suppliers. With employees returning to offices and resuming their former workplace behaviors, our challenge will be to continue this trend.

SUSTAINABLE OPERATIONS

Green Offices Update

As part of our commitment to achieving carbon-neutral operations, we design our new offices and major renovations according to green-building principles and implement energyefficiency upgrades to existing offices.

Ten office projects have received a green-building certification, and one is registered for certification. In 2021, our New York office became our first to receive a WELL Health-Safety Rating. And in 2022, we expect to earn our first Living Building Challenge petal certification, for our Denver office

Our office fit-out policy prescribes best practices in high-performance design for office moves and major renovations, helping create workspaces that are healthy, sustainable and inspiring.

Our 60 green champions help local offices meet energy-efficiency and emissionsreduction goals and other environmental and social objectives. They are guided by a firm-wide program that includes regular meetings, grants and our “TTTRAX” guide, which defines best practices for sustainable offices. In 2021, we awarded 28 grants to support the work of these local corporate-responsibility champions in 25 locations. Since 2013, the firm has given $282,000 to offices for socially and environmentally friendly initiatives – including composting and waste recycling, energy-efficient office equipment, wellness programs and funding to support volunteer days.

Our offices with green building certification:

• Chicago: LEED Gold & LEED Platinum renovation

• Denver (former location): LEED Gold

• Denver: Living Building Challenge Petals (pending)

• Fort Lauderdale: LEED Gold

• Kansas City: LEED Gold

• Los Angeles: LEED Gold

• New York: LEED Gold and WELL Health-Safety

• San Francisco (former location): LEED Platinum

• Philadelphia: LEED Gold

• Washington, D.C.: LEED Gold

Our 5,500-square-foot Denver office is designed to achieve the Materials, Beauty and Place petals of the Living Building Challenge and is aiming for certification in 2022.

Luis Mauricio Perez/Thornton Tomasetti

SUSTAINABLE OPERATIONS

Progress Report: Sustainable Operations

Each year, we track several indicators that show progress toward achieving our sustainable-operations goals. The trends revealed by this data show us where we need to stay the course and where we need to make changes.

We add up the annual electricity use of individual offices to calculate the firm's total electricity consumption. For offices that are not individually metered, we estimate use by dividing the whole building's consumption by the proportion of the building we occupy. Electricity use rose with an increase in employees and locations over the years but has decreased since 2016 as a result of greater energy efficiency in our operations. Decreased office electricity use in 2020 and 2021 also reflects an increase in remote work due to the COVID-19 pandemic.

Total fuel consumption had risen following a large merger in 2015, which increased numbers of employees and office locations. However, it fell in 2020, possibly due to the increase in remote work during the pandemic. The firm’s opportunities for reducing fuel consumption are limited, as the fuel we use is primarily from heating our offices, we lease our office space, and HVAC systems are typically controlled by the building managers. We update fuel consumption in our greenhouse-gas emissions inventory every two years, so the most recent figure draws from 2020 data.

Our total carbon footprint captures the carbon emissions of our offices in five areas under Scopes 1 and 3: electricity consumption, heating and cooling, business travel by plane, employee commuting and office waste. This figure shows our carbon footprint before offsetting emissions (bars above), and our carbon footprint with offsets and renewable energy certificates (bars below). Carbon offsets and RECs have a significant impact on lowering our carbon footprint. In 2020 and 2021, our carbon footprint (before offsetting emissions) fell by as much as 32 percent – which in part can be attributed to the remote work and reduced business travel necessitated by the pandemic.

Our average carbon footprint per employee is an important measure of our energy-conservation efforts. It’s also used to determine reduction targets for our path to carbon neutrality. To calculate this metric, we divide total carbon emissions by the number of employees. This figure shows data before carbon offsets (bars above) and with offsets and renewable energy certificates (bars below). Our target for the year 2030 is an average carbon footprint per employee of 2.27 MT of CO 2 e; in 2021, we came close to achieving that target, with a footprint of 2.32 MT CO 2 e. To achieve carbon neutrality, we're aiming for high reductions of energy use paired with carbon offsets to neutralize remaining emissions.

This is the percentage of office products with “eco features” that we purchase from Staples, from which we purchase about 60 percent of our office supplies. Staples defines “eco features” as recycled content or compliance with environmental certification standards like Green Seal or the Forest Stewardship Council. This figure does not include an assessment of supplies purchased through other suppliers. The decline in green purchasing in 2020 and 2021 may be due to increasing our use of other suppliers and a resulting reduction in the variety and number of items we purchased through Staples

Green Champion Volunteers day with GrowNYC

Dom Ponsades/Thornton Tomasetti

HELPING COMMUNITIES

Community Service Update

Community service challenges our people to grow and helps build relationships in the communities where we live and work. Our Thornton Tomasetti Gives Back program aids people and communities in need and is a source of personal fulfillment for employees passionate about helping. Since its 2014 launch, the program, which pays staff for helping out in their communities, has resulted in more than 12,000 hours of service.

The program includes paid time for general community volunteerism, mentoring schoolchildren through the ACE Mentor Program , and a partnership to build bridges in remote communities with Bridges to Prosperity.

Our Volunteer Days benefit pays employees for up to two days of community service annually, including local activities ranging from assisting in soup kitchens to beach cleanups.

Understandably, due to social distancing and other limitations, use of this benefit dropped during the pandemic: before COVID, our community-service involvement was on the rise, with more than 2,000 hours logged in 2019. In 2021, 425 hours of Volunteer Days were taken.

Thornton Tomasetti Gives Back also sponsors the ACE Mentor Program of America at the national and local levels and compensates employees for half the hours they spend mentoring schoolchildren in the program. The firm has been closely involved with ACE since it was established in 1994 by Charles Thornton, one of our founding principals. During the pandemic, to avoid the risks of in-person volunteering, the majority of the program’s activities were carried out virtually. In 2021, 90 employees in 18 U.S. locations logged 906 hours of service with ACE on their time sheets, which is about 2,000 hours of actual service since half of hours are put to paid time.

The Thornton Tomasetti Gives Back Program also encourages employees to apply their technical skills in service to disadvantaged regions of world. Sadly, when the pandemic struck in 2020, our planned work with Bridges to Prosperity, building a third pedestrian bridge that would link an isolated Rwandan community to vital resources, was suspended due to travel restrictions. In 2021, we remotely sponsored the organization’s year-end campaign, the Thornton Tomasetti Third Bridge Challenge. We’re now planning a 2023 bridge build in Rwanda.

In 2021, the challenges presented by in-person community service led us to explore new ways of remotely offering our skills and time to people in need. We’re pushing toward our 2025 goals of 50 percent of employees participating in the Thornton Tomasetti Gives Back program and 100 percent awareness of company-provided opportunities for community service. And while our progress toward increasing service hours each year by 10 percent has slowed, we anticipate an increase of in-person volunteer opportunities and discovery of even more creative ways of helping communities and people in need in the year ahead.

Our Tampa office is one of 18 locations that participate in the ACE Mentor Program, teaching schootchildren about engineering principles and the AEC industry.

Judia Duran/Thornton Tomasetti

HELPING COMMUNITIES

Charitable Giving Update

As a Bridges to Prosperity partner, we’ve seen firsthand how bridges can transform rural communities by giving them better access to vital resources. Bridges to Prosperity's work is making a real difference in people’s lives – and we’re very happy to support it.

— Amy Hattan, Thornton Tomasetti Corporate Responsibility Officer

In 2021, Thornton Tomasetti, Inc., gave $305,129 to help educate the next generation of AEC professionals, provide physical infrastructure to underserved communities, and support a variety of charities that are doing good work in our communities. Donations by our local offices represented 17 percent of our contributions, supporting causes like the March of Dimes, the Alzheimer’s Association, Rebuilding Together, the United Way, the American Cancer Society, Canstruction and more.

Total donations grew 56 percent over the previous year, in which giving was affected by pandemic-related changes in programming and sponsorships.

The majority of our 2021 charitable donations supported the Thornton Tomasetti Foundation a 501(c)(3) organization whose contribution priorities are like those of the corporation.

While our work in 2021 with Bridges to Prosperity was suspended due to travel restrictions, we collaborated remotely with the organization to sponsor its year-end campaign, the Thornton Tomasetti Third Bridge Challenge. We’re planning to visit Rwanda again in 2023, to build another footbridge connecting isolated communities to economic opportunities, education and healthcare.

Our charitable giving continues to rise toward pre-pandemic levels, a trend we expect to continue for the foreseeable future.

Our New York Canstruction 2021 submission, inspired by Sol LeWitt's Wall Drawing #1136 won the Most Cans (9,698) award. For Canstruction competitions, design professionals build structures from cans of food, which are later donated to local food banks.

Lorenzo Sanjuan/Thornton Tomasetti

HELPING COMMUNITIES Thornton Tomasetti Foundation

The Thornton Tomasetti Foundation is an independent 501(c)(3) organization that funds scholarships and fellowships for graduate and undergraduate students in building engineering, design and technology. It also supports people and organizations pursuing philanthropic activities in these areas.

In 2021, the foundation granted $162,250 in scholarships and charitable contributions, including $41,250 to six college students through its Thornton Tomasetti Foundation National Scholarship program, Student Innovation Fellowship and Technical Literacy Fellowship. Charitable organizations that have received funds include Engineers in Action, the Marconi Society, Urban Assembly School, Geohazards International and Archive Global.

Since its inception in 2008, the foundation has distributed $1,460,950 in grants and scholarships.

The University of Southern Indiana chapter of Engineers in Action helped replace a flood-damaged crossing over the Mud Fork River in Spencer. West Virginia.

Courtesy Engineers in Action USI Chapter

Richard Tomasetti Chairman, Thornton Tomasetti Foundation New York

HELPING COMMUNITIES Progress Report: Helping Our Communities

Each year, we track several indicators that show progress toward achieving our community-service and philanthropy goals.

The company-paid community service metric tracks "onthe-clock" hours our employees spent in community service activities, including hours for local volunteerism through our Volunteer Days benefit and half of the hours they spend participating in the ACE Mentor Program. While the long-term trend is increasing participation, the COVID-19 pandemic limited in-person service opportunities and delayed the construction of a Bridges to Prosperity project in Rwanda until 2023.

Our Volunteer Days benefit allows employees to receive up to two paid working days a year for service in their local communities. This metric tracks time posted to the "volunteer day" code on time sheets. It does not include volunteerism by employees on their personal time. Recent years show atypically low hours because of the COVID-19 pandemic – yet a rise in number of hours in 2021 may herald a return to normalcy.

We track company-paid ACE Mentor Program participation which is the amount of time U.S. employees spend as mentors or board members with the ACE Mentor Program of America. ACE volunteers are paid for 50 percent of their participation hours – an average of 15 per year – with the remainder a contribution of their personal time. With a change to remote programs during the pandemic, our employees were able to continue to serve as mentors virtually.

Charitable contributions include all payments in each year coded as “donations” in our accounting system. This includes annual contributions – such as those to the Thornton Tomasetti Foundation – and donations by our offices to local charities, which vary from year to year. The overall trend has been toward increasing philanthropy, but during the pandemic, spending was reduced.

BUILDING GREAT WORKPLACES

We Strive to Cultivate a Welcoming & Rewarding Environment

Lorenzo Sanjuan/Thornton

BUILDING GREAT WORKPLACES

Equity, Diversity & Inclusion Update

When we launched our corporate responsibility initiative 10 years ago, one of our goals was to increase the firm’s gender, ethnic and racial diversity. In 2016, we established an inclusion and diversity committee. Its mission was to build an inclusive environment where people are respected for who they are and free to thrive.

By 2020, we realized that our initiative needed to go further, so we reimagined our committee and deepened our mission to include equity.

Our three employee network groups (ENGs), Women@TT Mosaic (focused on multicultural issues) and Spectrum (LGBTQIA+), support our equity, diversity and inclusion (ED&I) goals. As the ENGs mature and grow, they develop more programs to engage and educate us all. (See our Annual Review for a timeline of activities)

Our efforts are paying off, not only by creating a welcoming, lifestyle-friendly workplace, but also by earning industry recognition: Thornton Tomasetti was among nine companies that received the American Council of Engineering Companies of New York’s 2022 Diversity, Equity, Inclusion & Belonging award in its inaugural year.

In 2021, to fortify our commitment to equity and diversity, we began voluntarily participating in the Human Rights Campaign’s Corporate Equality Index, a national benchmarking tool that rates and reports on corporate policies, practices and benefits related to lesbian, gay, bisexual, transgender and queer workplace inclusion. We’re off to a good start: in our first year of participation, we received a 90 percent rating. And using this year’s score sheet as a road map, we’ll continue working toward a perfect score – and recognition as one of the HRC’s “Best Places to Work for LGBTQ Equality” – in 2023.

Employees celebrate International Women's Day on March 8, 2022.

Lorenzo Sanjuan/Thornton Tomasetti

BUILDING GREAT WORKPLACES

Lifestyle-Friendly Workplace

In 2021, the second year of the pandemic, COVID-19 continued to loom large. The bulk of our employees continued to work remotely, and mental health issues were a major concern for people everywhere. In response, we expanded our employee assistance program internationally and increased communication about our wellness tool kit.

Health safety was especially important for employees returning to work in person, and 384 of our people moved into our new New York headquarters , which recently earned the International WELL Building Institute Health-Safety Rating.

Notably, use of paternity leave rose (see GRI Content Index 401-3) this year, with 30 fathers claiming the full six weeks of paid leave (maternity leave is 10 weeks), either consecutively or nonconsecutively. Our fitness reimbursement (188 participants) and student loan matching (15 enrollees) programs also remained popular.

A 2021 voluntary employee survey with 83 percent participation revealed that 76 percent of our employees are satisfied with their current benefits. In 2020, we rolled out new wellness benefits in response to the pandemic, and in 2021, we continued to offer all employees membership in a meditation and mindfulness program and free installation and use of a fitness steps application. Our ongoing financial wellness seminars engaged 40 percent of our employees. And our corporate responsibility grants program assisted 18 of our offices with employee wellness improvements such as healthcare kits, yoga classes, healthy food, air purifiers, ergonomic equipment, and other items and activities.

Employees in our London office breathe cleaner air filtered by a new purifier awarded to the office through a corporate grant.

Thornton Tomasetti

BUILDING GREAT WORKPLACES

Training & Education Update

Thornton Tomasetti made a commitment to vitality, and we’re looking to develop the future skill sets that will contribute to our enduring organization. Our partnership with the Roux Institute will help our people develop cuttingedge skills and will advance our knowledge of AI internally and industry-wide as we create pathways to sharing our knowledge within the profession.

—

Robert Otani, Chief Technology Officer, Thornton Tomasetti

One of the pillars of Thornton Tomasetti’s training and education program is mentorship throughout an employee’s tenure. Mentoring builds relationships and helps employees understand what it takes to be successful. In 2021, we expanded our formal mentoring program – originally offered only to women, due to the known challenges they face in AEC professions – to include people of all genders. By subscribing to a new mentorship platform, we were able to automate processes that allow us to offer mentoring to 74 percent more employees and to administer the program at a higher level. In 2021, 312 people signed up to be mentors and 404 employees were offered a mentor in the first six-month period. The opportunity for mentorship will rotate to a new group in the next series.

We continued to develop our existing training programs with multiple delivery strategies (see GRI Content Index 404-1) Our entire staff has access to 600 online courses, which offer continuing education credit, and to regular Thornton Tomasetti University seminars (48 seminars in 2021). Our project management training involved 61 associates in a two-day program and completion of 430 online training sessions in 10 offices. Soft skill training is internally designed to provide insight into requested topics such as delegation, communication, management and leadership.

A new partnership with the Roux Institute at Northeastern University in Portland Maine, presents a unique opportunity for forward-looking skill development. As a corporate partner, we have agreed to collaborate on educational and resource offerings and to sponsor and fund employee participation. In the first year of this industryacademic collaboration, we enrolled 20 practitioners in courses tailored to our people’s

interests in artificial intelligence (AI) and machine learning. We also enrolled 26 of our leaders in an AI overview workshop by the Roux Institute. These trainings generated ideas for implementing this innovative technology in the firm’s work.

In addition to increasing the depth of our mentoring, group coaching programs and formal training opportunities, we’re preparing next-generation leaders for responsibilities that lie ahead as they advance in their careers. In 2021, the first cohort in our Action Leadership Challenge completed a two-year program of leadership training, self-assessment and collaboration on initiatives to support the firm’s fiveyear strategic plan. Our employee network groups and communities of practice (CoPs) involve learning activities and a significant amount of networking and organizational development. Our 30 CoPs, topic-focused knowledge management groups open to all employees, engage 52 percent of employees in the sharing of ideas across practices and offices.

Thornton Tomasetti employees worked together on student projects as part of a Roux Institute at Northeastern University course on machine learning. This diagram depicts one team’s solution to building an environmental and energy performance prediction system.

Progress Report: Building Great Workplaces

Each year, we report on several indicators that show progress toward achieving our goals for inclusion and diversity, professional growth and a lifestyle-friendly workplace.

Retention of female employees is one indicator of a viable pipeline for the advancement of women into positions of senior leadership. Our rate of retention remains high, at 83 percent during the pandemic and when many companies were experiencing low rates of retention.

Hires of women and employees of nonwhite ethnicity or race tracks our progress toward more diverse hires. During the COVID-19 pandemic, our overall number of new hires fell.

The

The percentage of employees of nonwhite ethnicity or race is based on self-reported employee records.

U.S. employees who are women or of nonwhite ethnicity or race is based on self-reported records of employees who work in the United States.

Employees with ownership tallies the share of employees who are stockholders. Ownership opportunities are offered based on merit at the level of vice president and above. This number is dependent on the number of shares available for sale in a given year.

Retention of Female Employees

ESG DISCLOSURES

U.N. Sustainable Development Goals

GRI Content Index

Environmental Policy (external link only)

Ethical Sourcing (external link only)

Compliance (external link only)

U.N. Sustainable Development Goals

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Thornton Tomasetti contributes in a significant way to many of the United Nations’ Sustainable Development Goals. As a multipractice firm with more than 100 capabilities , we apply scientific and engineering principles across disciplines to solve the world’s challenges. Our impact stretches across many of the U.N.’s global goals.

End poverty in all its forms, everywhere

By contributing to the development of affordable housing projects through research, 3D printing and design of projects – such as our work with the City of Portland Homeless Service Center (Maine) – Thornton Tomasetti is working toward ending poverty. Additionally, our Thornton Tomasetti Gives Back program and the Thornton Tomasetti Foundation support nonprofit organizations like Bridges to Prosperity and invest in impoverished communities in underresourced regions of the world.

Ensure healthy lives & promote well-being for all, at all ages

We promote healthy living and well-being for our employees and the communities we serve through our work. Our employees receive excellent, affordable health insurance, annual fitness reimbursement, generous family leave for new parents, and free access to fitness, mindfulness and other wellness programs. Our largest office, our New York headquarters, is certified through the WELL Health-Safety standard to ensure a safe work environment during the COVID-19 pandemic and beyond. Our team of sustainability experts has worked on more than 450 green building certification projects and helped clients realize their project certification goals toward standards like WELL, WELL Health-Safety, LEED, BREEAM and the Living Building Challenge, as well as others that seek to improve the health and well-being of building occupants – in projects as diverse as schools and airports.

Ensure inclusive & equitable quality education & promote lifelong learning opportunities for all

This goal is woven into the fabric of Thornton Tomasetti. Founding Principal Charles Thornton launched the ACE Mentor Program of America (ACE) – a free after-school program designed to attract high school students into AEC careers –28 years ago. Around 70 percent of ACE mentees are minority students, and over 90 percent of our offices in cities where ACE chapters exist participate. Thornton Tomasetti, Inc., funds several scholarships for engineering students and offers regular internships, and the Thornton Tomasetti Foundation offers fellowships and scholarships for undergraduate students planning to pursue graduate studies in building engineering, design or technology. Many of our professionals are educators at colleges and universities worldwide. Within our firm, we offer our employees discretionary tuition reimbursement toward a degree program or for relevant courses.

U.N. Sustainable Development Goals

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Achieve gender equality & empower all women

& girls

Thornton Tomasetti aspires to be an industry leader in fostering the professional advancement, success and visibility of women, not just at all levels of our firm, but also in the engineering field. A passion for gender equality and innovation through diversity drives our efforts to increase our number of female shareholders and employees, encourage women to become involved in company management, empower women through our Women@TT employee network group and encourage girls to enter STEM professions. Our Equity, Diversity and Inclusion and Women@TT initiatives promote education of all employees regarding challenges faced by women as a gender underrepresented in our industry. These initiatives create opportunities to improve inclusion for women, foster a supportive community for women in our firm at all stages of their professional development, and help create a culture in which women are treated equitably and inclusively.

Ensure access to affordable, reliable, sustainable & modern energy for all

Thornton Tomasetti's work in decarbonization supports the goal of achieving affordable and clean energy globally. We are helping decarbonize the power sector and heavy industry by minimizing the risks associated with carbon capture and storage technologies and onshore and offshore energy facilities. We are also advancing technologies for more efficient energy storage and electrifying transportation systems. Our engineers apply their expertise to solving the structural and functional challenges of alternative energy systems. Our sustainability experts guide clients to pursue embodiedcarbon reduction energy efficiency and netzero-energy buildings. We fund renewable energy by purchasing renewable energy certificates to reduce the greenhouse gas emissions generated by our offices’ electricity consumption, as well as by buying carbon offsets for our business travel.

Ensure availability & sustainable management of water & sanitation for all

Our sustainable design projects – to which we apply our expertise to meet a broad range of sustainability objectives – contribute to the goals of clean water and sanitation. We assist our clients in meeting green building certification water efficiency and net-zero water credits by helping them establish a water budget for their projects and employing programs like LEED and the Living Building Challenge. Our projects reduce water use and take a holistic water budget approach, especially in places like California, where drought is common. We provide services in green infrastructure and master planning natural habitat regeneration through our resilience practice. These services support water solutions based on climatic analysis at a building and site level and provide for stormwater management.

U.N. Sustainable Development Goals

(Page 3 of 4)

Promote sustained, inclusive & sustainable economic growth, full and productive employment & decent work for all

Attention to diverse and nondiscriminatory recruitment and company policy means that Thornton Tomasetti contributes to the goal of decent work and economic growth opportunities for all. Our company standard practices and healthy work environment support our employees. Our work on a variety of projects, across a range of sectors, contributes to economic growth. Many of them, such as the Order of Saint Francis Healthcare headquarters in Peoria, Illinois, and Capital One Center in Washington, D.C., contribute to community development, offering new avenues for economic growth. Through our R&D and innovation accelerators, we contribute new technologies to the building sector and beyond, and we support entrepreneurship through AEC Angels, which funds technology start-ups.

Build Resilient Infrastructure, Promote Inclusive & Sustainable Industrialization & Foster Innovation

Thornton Tomasetti’s innovation engine, CORE studio, develops innovative and dynamic tools that improve efficiency and enable us to provide optimized client solutions. This positively impacts the quality of the infrastructure in the cities where we work. Every year, R&D funding is made available to employees in an open call for innovation developments. TTWiiN, our technology accelerator, commercializes some of these developments. Our services contribute directly to the industry, innovation and infrastructure goal. Our resilience consulting helps clients prepare, endure, adapt and thrive in a disruptive and changing world. In addition, we’re working with hospitals and subways to develop resilient infrastructure designs. Our Applied Science practice engages in research, development and design to engineer practical solutions that manage risks across a range of military and civilian applications.

Reduce inequality within & among countries

Thornton Tomasetti applies fair employment policies and equitable wages across our 40-plus offices and in our work in more than 50 countries. The company assesses pay parity to ensure income equity. Our Equity, Diversity and Inclusion initiative and antidiscrimination policies help ensure equal opportunities for all employees. We promote involvement in our ED&I employee resource groups across locations as far-flung as Mumbai, India, and Washington, D.C. By sharing our technology and expertise across locations, we contribute to greater equality among countries. Our designs of buildings and communities can have a secondary effect of increased social equity. Our service work in Rwanda with Bridges to Prosperity helps reduce inequality for underresourced and isolated communities.

U.N. Sustainable Development Goals

(Page 4 of 4)

Ensure sustainable consumption & production patterns

Per our environmental policy, we aim to apply our embodied-carbon specifications so that our projects use materials or adjustments to materials that are less carbon intensive than typical choices are. Since buildings produce 40 percent of global CO 2 emissions, and about 11 percent of those are from building materials, our embodied-carbon action plan commits us to advocate for the use of low-embodied-carbon or carbon-storing materials within our sector and adjacent industries.

Another area of impact is the selection of healthy materials. We avoid the use of toxic materials on the Living Building Challenge Red List and endeavor to influence clients and partners to choose responsible material consumption and production. We contribute to a circular economy through our master-planning projects, into which we incorporate circular economy principles.

Take urgent action to combat climate change & its impacts

We’re combating climate change through our internal policies, projects and services, and advocacy and partnerships. We participate in committees focused on reducing emissions in our industry and sponsor organizations like the Carbon Leadership Forum. We promote and apply creative means to reduce carbon in our projects and are committed to achieving carbon-neutral business operations and influencing policies and practices for sustainability and resilience in our industry and communities. We’re a recognized leader in moving consideration of embodied carbon to the forefront of our industry. We coinitiated the Structural Engineers 2050 Challenge, urging all structural engineers to understand, reduce and eliminate embodied carbon in their projects by 2050, and are an inaugural member of the Structural Engineers 2050 Commitment. Our sustainable design, decarbonization and resilience services help clients combat climate change and its impacts.

Make cities & human settlements inclusive, safe, resilient & sustainable

Thornton Tomasetti provides consulting services in resilience and sustainability, which positively impact the goal of sustainable cities and communities. Our work in all our practice areas requires that we honor our oath as engineers to protect public safety in the communities we serve. We’re committed to constructing a cleaner, healthier built environment by measuring, tracking and eliminating embodied and operational carbon in buildings and neighborhoods. We collaborate with other firms to create high-performance, low-energy facilities and communities that are efficient, comfortable and healthful at every stage of their life cycles.

Our broad range of sustainability services – from water balancing, green building certification, circular economy guidance and healthy materials research to parametric energy analysis –contributes every day to creating sustainable cities and communities.

Protect, restore & promote sustainable use of terrestrial ecosystems

Master planning is an opportunity to maximize long-term sustainability and resilience. We help communities develop sustainable master plans, encouraging biodiversity and habitat regeneration. We also recommend green spaces to co-benefit stormwater management and heat mitigation. This enhances wildlife corridors and creates habitats that may not have existed in urban settings. We recognize that mass-timber construction has great potential to reduce embodied carbon and that reducing carbon means sustainably managing forests. We are structural engineer for the world’s tallest masstimber tower. As a leader in mass-timber design, we have an opportunity to impel wood suppliers toward more sustainable practices. Our structural engineering work includes green roof design. Green, vegetative roofs can provide unique habitats for biodiversity in urban settings.

GRI Content Index

GRI 1: Foundation 2021

Thornton Tomasetti has reported the information cited in this GRI content index for the period January 1, 2021, through December 31, 2021, with reference to the GRI Standards.

ESG DISCLOSURES

GRI 2: General Disclosures 2021

2-1 Organizational details

2-2 Entities included in the organization’s sustainability reporting

2-3

Reporting period, frequency and contact point

2-6 Activities, value chain and other business relationships

2-7 Employees

(Page 1 of 8)

Thornton Tomasetti

Nature of ownership: Private, employee-owned corporation

Headquarters: New York City

11 Countries of Operation: ThorntonTomasetti.com/Contact-Us

All subsidiaries and joint ventures associated with Thornton Tomasetti, Inc., are covered in the report.

Year 2021 annual reporting: January 1, 2021, through December 31, 2021

Publication date: June 15, 2022

Financial reporting: May 2022

Contact: Amy Hattan, Corporate Responsibility Officer, AHattan@ThorntonTomasetti.com

Activities: T horntonTomasetti.com/Capabilities

Sectors: Private; architecture, engineering and construction (AEC); building sector; consulting Markets: www.ThorntonTomasetti.com (Client Solutions)

Value chain:

• Upstream (construction materials, computing supplies, office products, contracted labor and project subcontractors to supplement workforce)

• Downstream (buildings and other structures, infrastructure, clients - contractual relationships)

• Operational supply chain: Leased buildings and vendors (IT, office supplies)

Our data includes continuous staff. We did not include seasonal workers, interns, temporary staff, or retirees in the data set unless specified. Full-time/part-time is defined by the respective country of work. Gender of employees is self-designated.

ESG DISCLOSURES

GRI 2: General Disclosures 2021

ESG DISCLOSURES

GRI 2: General Disclosures 2021 (Page 3 of 8)

2-9

structure and composition

Number of Part-Time Employees by Gender and Region

Part-time is defined by country of operation as being any work schedule less than the full standard hours each week of work.

Our highest governance body responsible for decision-making and overseeing the management of impacts is our board of directors. The board comprises 12 employees and one external member. All employees on the board hold executive positions in the firm. See our leadership page for roles and competencies of board members. For diversity of leadership, see disclosure 405-1.

Our governance structure is organized as a matrix, with regions, practices and departments reporting to the coCEOs, who report to the board. The co-CEOs manage the company, and the board assures that the company is effectively managed. Board members serve two-year terms, with no term limits. Every two years, membership is reviewed and put to shareholder vote at the annual meeting.

The corporate responsibility steering committee and the equity, diversity and inclusion committee are management committees responsible for working with the CEOs on decision-making for ESG impacts. The corporate responsibility department helps develop firm-wide goals and drive policy implementation. 2-10

Nomination and selection of board members are done at the election of the board and coordinated by the board chair. Both existing and new board members are evaluated on past performance. Ownership is one criterion for board membership but is not necessary, as we allow for external members, who cannot hold stock.

GRI 2: General Disclosures 2021 (Page 4

of 8)

2-11

Chair of the highest governance body

2-12

Role of the highest governance body in overseeing the management of impacts

The board chair is Thomas Scarangello, former CEO. Conflicts of interest are prevented by the chair not being the same person as the CEO. The chair is a senior executive but is not the highest governing individual in the firm.

The firm’s leadership structure provides checks and balances. The CEOs report to the board, and the chair reports to the CEOs. This arrangement provides the firm with the best level of governance and an appropriate number of checks and balances.

Members of our highest governance body are directly involved in the oversight of the organization’s impacts on the economy, the environment and people. The CEOs manage the company and set the direction for the management of impacts, in collaboration with senior leadership. The board challenges and supports, assuring that policies are effective in building an enduring organization and in representing shareholder interests. The CEOs meet with the board quarterly. The management approach is driven down to the matrix leaders. Wherever viable, hard metrics are set and we execute our programs to meet those metrics, which the board reviews quarterly to ensure the direction meets the stakeholders’ vision.

One of the co-CEOs is a member of the corporate responsibility steering committee and the direct supervisor of the corporate responsibility officer. The corporate responsibility steering committee is composed of leaders representing a diversity of our locations, practices and departments. This committee updates our goals for management of the organization’s impacts on the economy, environment and people every five years. The president and a board member are executive advocates of the equity, diversity and inclusion committee. They work with our employee network group leaders to weave ED&I into our company and culture. These processes are inclusive of employee stakeholders, and they are influenced by our clients’ interests.

The corporate responsibility officer, reporting to one of the co-CEOs, is a senior member of the staff, responsible for managing some of the impacts. Corporate responsibility is thread into our culture at Thornton Tomasetti, and therefore management responsibility is delegated to leaders in the areas most relevant to specific impacts. In addition to the corporate responsibility department, this includes our equity, diversity and inclusion committee; our human resources department; our legal department; our sustainability practice, etc. A regular weekly call between our department leaders and executive team enables regular reporting, as do lines of supervision between managers and the CEOs.

GRI 2: General Disclosures 2021

2-14

The highest governance body is responsible for reviewing and approving the reporting information. Reviews take place via regular weekly department leader/executive leader meetings and regular meetings between the coCEO and the corporate responsibility officer. The co-CEO approves a final review before the sustainability report is released.

2-15

The interests of all senior and executive leadership, the board and stakeholders are aligned around our purpose and values. This mitigates conflicts of interest: the board is in agreement with the direction of our purpose and values. Our five-year plan is clear about the company’s direction during any five-year period, and the board ensures that we are aligned with the five-year plan and our purpose and values. 2-16

The co-CEOs bring any critical operational concerns to the executive committee, and these concerns are discussed in this forum. Weekly meetings of the department leaders and executive committee also cover areas of critical concern. At the quarterly board meetings, concerns are discussed under the umbrella of strategy and vision. Then, messages about critical concerns are communicated to department leaders, practice leaders, regional leaders and employees via direct CEO town halls for their office locations. 2-17

The collective knowledge of the highest governance body on sustainable development is advanced through shared articles, invited speakers, internal seminars, conference attendance and involvement of individuals in industry associations. 2-18 Evaluation of the performance of the highest governance body

The first level of evaluation of our performance in sustainable development is at the CEO level. The board evaluates how the co-CEOs are performing in the areas of the economy, the environment and people. This evaluation happens over time. Ultimately, the shareholders will inform the board if the evaluation is effective. Shareholders and other employees learn about our performance, as does the board, through several communication channels. Shareholders can voice disagreement or agreement with the company performance in sustainable development semiannually when selecting and reappointing board members.

2-19 Remuneration Policies

Compensation decisions are conveyed through the matrix, from the top down. The board oversees CEO compensation, and the co-CEOs make compensation decisions for the firm.

ESG DISCLOSURES

GRI 2: General Disclosures 2021

(Page 6 of 8)

2-20 Process to determine remuneration

2-21 Annual total compensation ratio

Thornton Tomasetti adheres to a holistic compensation process consisting of elements of salaries, bonuses and equity. Our process is informed by firm performance, performance evaluations, project data and market conditions.

The ratios for annual total compensation and for the percentage increase for our highest-paid employee to the median in each country of significant operations follows.

and all bonuses except relocation and referral.

GRI 2: General Disclosures 2021 (Page 7

of 8)

2-23 Policy commitments

2-24 Embedding policy commitments

2-25 Processes to remediate negative impacts

Environmental Policy

Compliance

These policy commitments are approved by the executive committee and communicated via our website and employee handbook, and in our responses to requests for information.

Policy commitments are overseen by the department leaders and other senior leaders whose jurisdictions can have the greatest influence on the policy, with guidance and oversight from the CEOs. Staff in our departments and practices are rewarded with awards and bonuses and evaluated on how they embody the values outlined in our policies. Communication of our policies to our clients ensures compliance, as the results are seen in how we design our projects and how we deliver our services.

Thornton Tomasetti uses Navex Global, a confidential ethics reporting hotline, to enable employees to report workplace grievances. This hotline can be accessed by all employees through our intranet on either a smartphone or computer. Employees also have the option to call the hotline directly to file a complaint. Our human resources business partners (HRBP) are the only individuals with access to the account, and they monitor it regularly. Aside from the hotline, employees are encouraged to reach out to their local HRBP or the CHRO with any employee relations issues. As with the hotline, once an issue is reported, the local HRBP or CHRO follows up with the employee to understand the issue in more detail and decide which next steps are needed. Once the issue has been resolved, the HRBP requests feedback on the process, which enables stakeholders to help improve the firm’s processes. Each employee-relations issue is logged into a spreadsheet, and the outcome is recorded (e.g., involuntary/voluntary termination, retained employee).

By tracking the outcomes/retention, the firm is able to assess whether the processes are effective.

GRI 2: General Disclosures 2021 (Page

8 of 8)

2-26 Mechanisms for seeking advice and raising concerns

2-27 Compliance with laws and regulations

2-28 Membership associations

2-29 Approach to stakeholder engagement

Employees who seek advice and raise concerns start with their supervisors or other matrix leaders. These concerns roll up to department leaders, the executive committee or the board. If employees are not comfortable speaking with their supervisors or other leaders, they can express their concerns through our confidential hotline, Navex Global. See disclosure 2-25.

No instances of non-compliance in reporting period.

The membership associations in which we have significant (highest spend and most engagement on committees) involvement include the American Institute of Architects, the ACE Mentor Program of America, Beverly Willis Architecture Foundation, Urban Green Council, Structural Engineers Association of New York, Chicago Architecture Center, Council on Tall Buildings and Urban Habitat, American Council of Engineering Companies and the New York Building Congress.

Our significant stakeholders are clients, business partners, employees, governments, industry associations, shareholders, suppliers and underrepresented groups. We engage with stakeholders to identify materiality areas for our sector, to identify areas of concern and reduce negative impacts, and to involve our stakeholders in the solutions. We work as a team with our stakeholders and seek inclusion for our employees in decision-making.

GRI 201: Economic Performance

201-1 Direct economic value generated and distributed

201-2 Financial implications and other risks and opportunities due to climate change

See Financial Progress Report .

We do not engage in profit distribution to shareholders. We are a private company and do not publish profit or operational costs.

The risks and opportunities posed by climate change that have the potential to generate substantive changes in our operations, revenue or expenditures include physical risks such as extreme weather, shortages of materials, and health pandemics that impact our employees; new competition from a change in demand for particular services and new technologies; and civil unrest that can result in uncertain markets in our locations. Our New York headquarters weathered Superstorm Sandy, and following this extreme weather event, we developed a business-continuity plan to reduce risk.

As an engineering services firm that provides sustainable design services, we have an opportunity to be competitive and to quickly respond to changes in demand for sustainability services as more policies and codes demand sustainable design and as more clients seek advances in sustainability in their projects. We have a great opportunity to apply our expertise and capacities toward solving climate change problems. We are expanding our service areas in climate change mitigation and adaptation. We are also developing new technologies that can be used toward reducing greenhouse-gas emissions and in strengthening resilience against climate-change impacts. We are progressing toward our goal of carbon-neutral business operations by 2030 by improving energy efficiency in our offices, purchasing green power, and using carbon offsets to mitigate emissions from business travel.

201-3 Defined benefit plan obligations and other retirement plans

201-4 Financial assistance received from government

Thornton Tomasetti offers a defined contribution plan. U.S. employees may select a pretax contribution percentage, subject to the annual limit set by the U.S. IRS. The firm makes a matching contribution of 50 percent to the first 7 percent of employee contributions, not to exceed the maximum current-year tax-deferred limit.

Thornton Tomasetti did not receive financial assistance from government in the reporting period.

ESG DISCLOSURES

GRI 302: Energy

302-1 Energy consumption within the organization

302-2 Energy consumption outside of the organization

302-3 Energy intensity

302-4 Reduction of energy consumption

302-5 Reductions in energy requirements of products and services

See: Sustainable Operations Progress Report

Electricity consumption: 10,835,611.2 megajoules

Heating consumption: 7,040,387.69 megajoules

Total nonrenewable energy consumption (purchased) within the organization: 17,875,998.9 megajoules

See Our Good Work Progress Report

Energy intensity ratio: 17,875,998.9/1,233 = 14,497.97 Megajoules (14.5 GJ) per employee

Organization-specific metric: 1,233 employees counted in 2021 emissions analysis Energy included: Purchased fuel and electricity consumed within the organization

Reduction of energy consumption in our operations is possible where we have direct control in our leased office spaces. We can measure gains in energy efficiency resulting from designing our new offices to a green building standard by comparisons with average energy use intensity. We can also measure gains in efficiency from changes in our computing technology.

Eleven of our offices have been certified or are registered with a green building certification program such as LEED. The energy use reduction in lighting power intensity from a LEED Commercial Interiors project is an average of 20 percent.

Thornton Tomasetti has made a concerted effort over the last 10 years to switch from desktop computers to laptops. In 2012, 60 percent of staff worked primarily from a desktop computer. In 2021, the majority of staff used laptops. Considering the rated power of the standard-issue workstation (950 W), compared with the rated power of the standard issue mobile workstation (90 W), we have realized a 91 percent reduction in possible energy usage per switch. By migrating 105 individuals from desktop machines to laptops in 2021, we saw a 7 percent reduction in energy usage from personal computing.

See:

• Our Good Work Progress Report

• Embodied Carbon Showcase

Our sustainable design services contribute to reductions in the energy requirements of buildings. We offer our clients consulting to help them meet project goals for energy efficiency, net-zero energy design, passive house, life-cycle assessment and embodied-carbon reduction, and LEED and other green building certifications.

GRI 305: Emissions

ESG DISCLOSURES

GRI 401: Employment (Page

1 of 4)

ESG DISCLOSURES

GRI 401: Employment

(Page 2 of 4)

ESG DISCLOSURES

GRI 401: Employment

401-2 Benefits provided to full-time employees that are not provided to temporary or part-time employees

(Page 3 of 4)

Full-time and part-time U.S. employees regularly working a minimum of 30 hours per week are eligible for the Thornton Tomasetti benefits plans below. Other countries have similar offerings and differ based on local law and benefit norms.

• Cigna medical plans (employer/employee paid)

• High medical OAP

• Low medical OAP

• High deductible health plan with health savings account

• Cigna dental plan (employer/employee paid)

• Dental PPO

• EyeMed vision insurance (employer paid)

• Provides eye exams and offers discounts on lenses, frames and contacts

• Life insurance (employer paid)

• Basic life and AD&D insurance for $100,000

• Voluntary life (employee paid)

• Employees may purchase life insurance for employee or spouse/domestic partner

• Short-term disability (employer paid)

• Provides partial replacement income due to disability, up to a maximum of 26 weeks

• Long-term disability (employer paid)

• Provides partial replacement income in case of disability from 90 days to age 65 years.

• Employee assistance program (employer paid)

• This confidential program assists employees and their dependents with personal problems and/or workrelated problems that may impact their job performance, health, or mental and emotional well-being.

• Offers other services and information on elder care, pet care, financial, emotional health, physical health, job/career, relationship, family life, legal, and substance use.

• Flexible savings pretax accounts (employee paid)

• FSA healthcare

• FSA dependent care

• Limited purchase FSA

• Fitness program (employer paid)

• Fitness reimbursement up to $400 paid in a 12-month period

• Bicycle program (employer paid)

• Bicycle reimbursement up to $240 per year

• Commuter pretax benefits (employee paid)

• Parking

• Transit

GRI 401: Employment

401-2 Benefits provided to full-time employees that are not provided to temporary or part-time employees (cont.)

(Page 4 of 4)

401-3 Parental leave

• Health savings account (employer/employee contribution)

• HSA available for employee enrolled in the high deductible health plan

• Receives employer new hire and annual contributions

• Employee may contribute to HSA

• Contributions are based on annual IRS limits

• Raymond James (employer paid)

• Offers one-on-one financial advice to improve employees’ financial health and provides a monthly series of webinars covering financial planning topics.

• 401(k) profit sharing plan (employer match/employee contribution)

• Retirement savings plan that allows employees to save and invest a portion of their earnings on a pretax basis.

• 50 percent match, up to 7 percent employee contribution

• 401(k) student loan matching program (employer match)

• Enables employees who are repaying a student loan to save for retirement while continuing to pay down their student loan(s).

• Cigna programs, wellness tools and applications (employer paid)

• Voluntary programs (employee paid)

• Critical care insurance

• Hospital care insurance

• Accidental injury insurance

• Wellness apps (employer paid)

• Walkingspree

• Headspace

Continuing full-time or part-time employees with a minimum of one year of service at Thornton Tomasetti who have become disabled due to pregnancy are eligible to receive full salary under the Parental Family Caregiver Leave benefit, based on years of service. Part-time employees’ leave days are in proportion to the average number of hours worked in the year preceding the beginning of leave. Paid family leave begins with the birth of the baby and is paid based on years of service.

Number that took parental leave: 17 women and 14 men

Number that returned to work after leave and were still employed 12 months after return: 14 women and 11 men

Return to work rates of employees that took parental leave: 100% women and 100% men

Retention rates of employees that took parental leave: 82% women and 79% men

GRI 404: Training and Education

404-1 Average hours of training per year per employee

6

404-2 Programs for upgrading employee skills and transition assistance programs See Training and Education.

404-3 Percentage of employees receiving regular performance and career development reviews

Performance alignments are optional for part-time staff (less than 30 hours).

99 percent completion of performance alignments (both male and female).

GRI 405: Diversity and Equal Opportunity

405-1 Diversity of governance bodies and employees See Inclusion & Diversity.

Percentage of Individuals Within Executive Committee and Board Governance Bodies by Gender

Percentage of Individuals Within Executive Committee and Board Governance Bodies by Age Group

405-2 Ratio of basic salary and remuneration of women to men

We are not including ratio of basic salary and remuneration of women to men in this report. We have a pay parity report that we publish internally every year based on specific technical job categories, but our categories do not currently match those of GRI.

GRI 406: Non-discrimination

406-1 Incidents of discrimination and corrective actions taken Our policies dictate that we respect the privacy and confidentiality of these sensitive matters, so numbers and details are omitted.

ESG DISCLOSURES

Company-specific materiality topic: Community Engagement

Company-specific materiality topic: Employee Health and Wellness

TTEHW-1 Employee engagement in wellness program

TTEHW-2 Employee satisfaction with benefits

See Lifestyle-Friendly Workplace.

See Lifestyle-Friendly Workplace.

www.ThorntonTomasetti.com

D.C. Cycle for Survival ride on May 21, 2022. Thornton Tomasetti