VISION ISSUE SIXTEEN | FALL 2023
Mechanical Considerations for Partial Renovation Projects Generally speaking, renovation projects can fall into one of two categories: partial renovation or total building overhaul. Typically, a partial renovation or addition is the more challenging of those project types and requires substantial multi-trade coordination. Just some of the challenges that are faced during a renovation are explained in this article. Structural Implications 1. Importance of Surveying Existing Conditions During design, engineers make a strong effort to survey existing beam heights and depths, as well as the location of existing penetrations, to ensure there is space for the new design. If field measurements are inaccurate, it can lead to more challenges in construction. In order to avoid that scenario, as design engineers, we conduct multiple field surveys to detail these constraints and compare them with the existing drawings to confirm potential routing, in areas where the ceiling is not accessible. 2. The Use of Existing Beam Penetrations and Risers Reusing existing penetrations and chases minimizes both the cost and coordination needed for the project, provided the new and existing systems are similarly sized. A downside of reuse, however, is that it locks the engineer into designing around field conditions that cannot not always be confirmed until demolition. 3. Additional Supports for New, Heavier Equipment The addition of heavy equipment such as air handling units, chillers, and cooling towers could necessitate supplemental supports. The structural
implications of system updates add cost and complexity to a project. As such, it is important that potential equipment locations are coordinated with the structural engineer as soon as possible in design.
Image 1: Existing Beam Penetration
Space Limitations 1. Limits on MER Space Energy recovery wheels might need to be added to meet current code requirements. This increases the overall unit size and footprint of the mechanical space required which might pose a challenge to new programming intents. 2. Low Floor-to-Floor Height and More Economical System Types If an existing building was constructed without HVAC, the floor-to-floor height could pose a challenge when fitting ductwork to meet modern ventilation and air conditioning requirements. Often, this situation prompts the design of a system with local heating and cooling (fan coil units, chilled beams, VRF) and a dedicated outdoor air system (DOAS), minimizing the ductwork size. Connecting to Existing Systems 1. Existing Versus As-Builts It is common for existing buildings to have undergone multiple renovations, some of which might not be documented. If possible, it is important to request As-Built drawings. Although existing ALL TEXT ©2023 KOHLER RONAN, LLC
design drawings are helpful, As-Builts will show the engineer how a design may have been altered in the field during construction. When such documentation is not provided, more field surveys will be conducted. 2. Testing and Air Balancing Oftentimes, there is intent to reuse existing equipment in a renovation. The full feasibility of that intent is not known until a pre-construction air/ water balancing report is done. Then, the engineer can determine if additional capacity needs to be added to serve the proposed new programming. 3. New Programming Versus Existing Systems The proposed architectural design might not allow the use of existing conditions due to ceiling height limitations or wall relocations. If existing piping or ductwork is located below the new ceiling height, it is critical to communicate with the architect and establish a minimum height for service runs. Additionally, if programming calls for a new room which encroaches on an existing shaft, the engineer will either have to relocate the existing systems or coordinate another solution. “Mechanical Considerations…” continued on page 2
IN THIS ISSUE Mechanical Considerations for Partial Renovation Projects
1
Lithium-ion Batteries and the Implications for Fire Protection
2
Did You Know?
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Project Highlight
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SUPPLEMENT Getting Up-to-Speed on Connecticut Plumbing Codes