Fire-Rated Corridor Substitution and Finish Request
During construction of a 12,000-square-foot medical office, the contractor submits an RFI: the drawings call for a 1-hour fire-rated corridor partition with 5/8-inch Type X gypsum board on both sides over steel studs. The proposed substitution is one layer of 5/8-inch Type X board on each side with mineral wool in the stud cavity and a listed sealant at the top track. The contractor says the substitution is equivalent and will save two weeks. Separately, the owner asks to substitute vinyl wall covering for paint in the corridor because it is cleanable. The corridor serves 14 exam rooms and is the only path to the rear exit. The building is sprinklered. The finish schedule already permits Type X board and painted gypsum. The contractor has not provided a listing or test report for the proposed wall.
1. Evaluate the contractor's proposed fire-rated assembly substitution. What must the architect require before accepting it?
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A 1-hour fire-resistance rating is not established by the presence of Type X board and mineral wool alone. It is a tested assembly with a specific listed design: stud type and size, stud spacing, number and orientation of board layers, fastener type and spacing, joint treatment, insulation, and penetration or top-of-wall detailing. The contractor's proposal may be equivalent, but the architect cannot accept it on the contractor's assertion. The phrase 'listed sealant at the top track' is also vague; the top-of-wall joint must match the listed assembly or an engineering judgment approved by the AHJ.
Before accepting, I would require a current listing or test report from a recognized testing laboratory, a detailed assembly description, product data for the board and insulation, and a comparison to the specified assembly. If the proposed wall is not listed as a 1-hour assembly, the contractor must either install the specified assembly or submit an engineering judgment from a qualified fire-protection engineer for AHJ review. I would also require a mock-up or inspection of the first wall segment before releasing the substitution. The two-week schedule saving is not a code argument; if the contractor wants the saving, the burden is on the contractor to prove equivalency. Because this corridor is the only path to the rear exit, I would treat the substitution as a life-safety submittal, not a routine product substitution.
2. Evaluate the vinyl wall covering request in the corridor. What fire and maintenance information do you need, and what would you recommend?
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The corridor is part of the means of egress, so the wall finish must meet the flame-spread and smoke-developed limits for the occupancy and location. Vinyl wall covering can be acceptable if it is a Class A material with a low smoke-developed rating, but the architect must verify the product data, the adhesive, and the substrate. The fact that the covering is cleanable does not answer the fire requirement. The building being sprinklered may affect the required finish class, but it does not eliminate the need to confirm the product classification.
I would request the manufacturer's flame-spread and smoke-developed test data, the adhesive data, and a sample of the installed system on the specified gypsum board. I would also check whether the covering is appropriate for a healthcare corridor where abrasion and disinfection are concerns; some vinyls are cleanable but can be damaged by certain disinfectants. If the product is Class A and compatible with the wall assembly, I would recommend approval with a written owner acceptance of the maintenance regime. If the data is incomplete or the product is Class B, I would retain paint or require a different covering. The decision should be documented in a supplemental instruction, not buried in an email.
3. How should the architect document and communicate these decisions?
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I would respond to the RFI in writing with a clear disposition: rejected, approved as noted, or revise and resubmit. For the wall assembly, the response should state that no substitution will be considered without a listed assembly or an engineering judgment accepted by the AHJ, and it should identify the specific submittals required. For the wall covering, the response should list the required fire test data and the conditions of approval. I would issue a supplemental instruction or formal substitution approval only after the data is reviewed, and I would copy the owner and contractor so the decision is not dependent on a verbal conversation.
The architect should also update the finish schedule and specification if the wall covering is approved, and require the contractor to maintain a sample and product data at the site. If the contractor proceeds without approval, the architect should document the nonconformance and require removal or a code review. The record should show that the architect evaluated life-safety and maintenance issues, not just schedule pressure.