Considerations for Wood Framing in Healthcare Buildings

CONSIDERATIONS FOR WOOD FRAMING

IN HEALTHCARE BUILDINGS

AUTHOR

Laura McLeod

AIA, LEED AP BD+C

CONSIDERATIONS FOR WOOD FRAMING

IN HEALTHCARE BUILDINGS

by Laura McLeod ABSTRACT

The purpose of this white paper is to outline key design considerations for an I-2 Occupancy building using Type VA construction, and discuss when this type of construction can be considered. The content of this paper is primarily based on experience and lessons learned through the design of an eight-bed inpatient hospice facility in Jasper County, SC. CASE STUDY

FoCH wanted their first inpatient building, located just outside of Beaufort in Jasper County, to feel like “home.” To create a welcoming, comforting environment for patients and their families, FoCH and the design team implemented a vision for a Lowcountry cottage style building with an aesthetic that feels more residential than institutional, inside and out. Warm, tactile materials include wood-look floors, shiplap walls, wood beams, and receptions desks and nurse stations that look like residential furniture.

The building houses eight patient rooms, shared spaces such as a living room and

Caroline’s Cottage Inpatient Hospice, Jasper County SC

kitchen/dining area separated by a dual-sided fireplace, a small library, children’s

Friends of Carolina Hospice (FoCH) was founded in 1977 as the first nonprofit

play area, meditation space, and reading nook. The staff amenities and respite

hospice organization in Beaufort County, SC. FoCH has been providing

areas include a break room, conference rooms, outdoor seating area, and walking

compassionate in-home care for over 40 years, and wanted to open an inpatient

trail around a pond.

facility to extend their care services to a wider community.

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The patient rooms are generously sized to allow for the family’s comfort, and

I-2 is further divided into two categories: Condition 1 and Condition 2. The

include a sofa bed, café table and chairs, wardrobe, ceiling fans, and private

primary difference is that I-2, Condition 1 is for facilities that provide medical

bathroom. Screened porches allow the patient beds to be rolled outside for

care, but do not provide emergency, surgery, or obstetric services or inpatient

natural light, fresh air, and views.

stabilization for psychiatric or detoxification. Examples of I-2 Condition 1 include nursing homes, foster care facilities, and inpatient hospice facilities.

I-2, Condition 2 is primarily for hospitals.

The lowest construction type allowable for I-2 is Type VA. IBC Tables 504.4 and 506.2 both indicate that VB is not permitted for I-2. Type VA will only allow for one story in height. Further, when looking at Table 506.2, VA limits building area to 38,000 SF when sprinklered, and 9,500 SF when non-sprinklered.

Smoke Barriers / Smoke Compartments Every story is required to be subdivided using smoke barriers into not less than two smoke compartments. Smoke compartments are limited to not more than 22,500 SF. Given the area limitations for Type VA in I-2, only two compartments should be needed.

The smoke barrier is required to fully separate one smoke compartment from the

The building is designed for future expansion of four additional beds as needs evolve.

other, from the top of floor slab to the underside of the roof deck or sheathing, so consideration should be made regarding the location in the plan as well as the

OVERVIEW Very few building types are appropriate for I-2 Occupancy and Type VA construction, but among them are nursing homes, foster care facilities, and inpatient hospice facilities. Given the area and height limitations of Type VA (further discussed under code considerations), this construction type may be an impractical design choice for some facilities such as nursing homes.

CODE CONSIDERATIONS I-2 occupancy is designated for buildings used for medical care on a 24-hour basis for more than five people who are not capable of self-preservation. Five or fewer occupants would be considered R-3 occupancy. In the 2018 IBC,

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roof configuration. If using a sloped roof, direction of the trusses should also be evaluated regarding the smoke barrier wall, so that constructability of the barrier continuity is not a factor.

The smoke barrier/smoke compartment separation is illustrated below. The double

using Type X gypsum sheathing to wrap into the opening to protect the wood

egress doors that are pocketed create a jog in the wall that can be seen as it

members (ex: Type X gypsum sheathing @ 40 min. + one 2X wood member @ 20

extends to the underside of roof deck. The smoke compartment was planned to

min. = 1 hour).

align with the roof bearing wall, but an additional gabled roof needed to be added (on the smoke compartment 1A side) to create a better transition to the low slope portion of the roof.

Incidental Use Spaces Incidental use spaces protected with fire barriers will need to be continuous to the underside of the fire rated roof/ceiling assembly. Details of the joint between the wall and the roof/ceiling assembly should be carefully considered and reviewed by the AHJ.

DESIGN CONSIDERATIONS Mixed Use Where there are mixed uses within the building, one strategy to consider if cost is a concern is to separate the I-2 portion of the building from Business and Assembly with a fire wall to create two separate buildings. This will keep the I-2 system requirements that are more costly and restrictive to a minimum and allow for lower grade systems to be used in the other occupancies as permitted by code for Type VA. Sloped Roof vs. Low Slope Roof If the design includes a sloped roof, the attic space will need to be sprinklered since it is combustible construction, and potentially draft stopped. Consider this in Fire Ratings

the cost of the project when contemplating the overall design of the roof.

Type VA requires exterior and interior bearing walls, floor and roof construction,

Acoustics

and primary structural frame to be 1 hour rated. While openings in fire rated

In an I-2 facility, acoustics are important for patient/occupant privacy, especially

bearing walls do not need to be protected (IBC 602.1) unless otherwise noted in

regarding HIPPA laws. When trying to determine partition types to meet “best

the code for other reasons such as fire separation distance, the structural integrity

practice” sound transmission control (STC) targets, wood framing offers limited

of the framing does need to be protected. Where openings occur in fire rated

testing options. Wood is a better transmitter of sound than metal studs, so the

bearing walls which have structural framing, such as at windows, the framing

wood assemblies by comparison have a lower STC rating than similar assemblies

can be protected in a multiple ways. One way is to provide enough wood framing

with metal studs. In order to achieve higher STC ratings, it may be necessary to

at the jambs and header to prescriptively add up to 1 hour (ex: three 2X wood

substitute standard gypsum board with a sound rated gypsum product which

members @ 20 min. each = 1 hour). Alternatively, the framing could be protected

increases cost.

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CONSTRUCTION SYSTEMS The decision to use wood framed construction should be carefully considered in any building type. There are many factors that contribute to the determination of wood vs. metal studs, some of which include:

in order to mitigate the risk for moisture and mold issues. However, with this envelope approach, the gable ends as typically framed presented an issue with maintaining this system. The outboard

• Mold

truss that would typically be aligned

• Termite protection

with the outside face of 2X wall framing

• Shrinkage and expansion

needed to shift inboard to allow for wall

• Construction detailing

framing to continue above the bearing

• Combustibility / fire ratings

height to the underside of roof decking.

This also created a need to determine how

Additionally, if the project delivery process is to bid out to general contractors,

that height of wood framing should be

for smaller projects that fit into the size range for this building type and

constructed. The bearing height is at 12’-0” and the height to the ridge of roof

occupancy, the project

is 13’-2” from the bearing height.

may draw residential scale contractors. It is important to indicate experience with I-2

MEP SYSTEMS

occupancy requirements in the

The design team will need to work closely with the MEP consultant to determine

qualifications to increase the

appropriate strategies and systems. Filtration requirements for I-2 limit the

likelihood of a well-managed

types of systems that can be used, and the use of residential-grade electrical

project. For the complexity of

components are restricted.

an I-2 occupancy, it would be advisable for the owner to have

Adding a drop plenum space below the roof rated assembly may reduce the

a CM on who that meets the

need for rated penetration of lighting, ducts, and devices and eliminate the need

qualifications and experience

for damper inspections. However, this strategy does increase the height of the

level for this type of building.

building and therefore increases cost.

The design includes continuous outboard insulation around the entire envelope, with batt insulation between the studs in the wall and secured below the roof sheathing, primarily

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CONCLUSION While the cost of wood framing may be less than that of metal framing, numerous other costs can be incurred due to the combustible nature of the structure for an I-2 occupancy. It is possible to develop a successful project using Type VA, but the factors discussed above should be considered before and during the design process.