LGreene
Registered User
Today someone asked me about a code requirement mandating a non-combustible transition strip under a door that leads to a dorm room, hotel, apartment, etc. This doesn't sound familiar to me. Has anyone run into this?
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Non-Combustible Transition Strip?
- Thread starter LGreene
- Start date
Doorman
Silver Member
From the 2013 Edition of NFPA 80 - Fire Doors And Other
Opening Protectives, Section 4.8.2 - Sills,
...Sub-section 4.8.2.1:"In buildings with noncombustible floors, a sill shall not be required, provided the floor structure is extended through the door opening."
Sub-section 4.8.2.2:"In buildings with combustible floors or combustible floor coverings, a sill shall be required if the floor structure is extended through the door opening, as combustible floor construction shall not be permitted to extend through the door opening."
Sub-section 4.8.2.3:"Door openings required to be protected by 1/2 hour or 1/3 hour rated fire protection for door assemblies shall be exempted from the requirements of [ Section ] 4.8.2.2."
Opening Protectives, Section 4.8.2 - Sills,
...Sub-section 4.8.2.1:"In buildings with noncombustible floors, a sill shall not be required, provided the floor structure is extended through the door opening."
Sub-section 4.8.2.2:"In buildings with combustible floors or combustible floor coverings, a sill shall be required if the floor structure is extended through the door opening, as combustible floor construction shall not be permitted to extend through the door opening."
Sub-section 4.8.2.3:"Door openings required to be protected by 1/2 hour or 1/3 hour rated fire protection for door assemblies shall be exempted from the requirements of [ Section ] 4.8.2.2."
Architect1281
Gold Member
Just a floor finish rating like here
804.4.1 Minimum critical radiant flux. Interior floor finish
and floor covering materials in exit enclosures, exit passageways
and corridors shall not be less than Class I in
Groups I-1, I-2 and I-3 and not less than Class II in Groups
A, B, E, H, I-4, M, R-1, R-2 and S. In all areas, floor covering
materials shall comply with the DOCFF-1 ―pill test‖
(CPSC 16 CFR, Part 1630).
Exception: Where a building is equipped throughout
with an automatic sprinkler system in accordance with
Section 903.3.1.1 or 903.3.1.2, Class II materials are permitted
in any area where Class I materials are required,
and materials complying with the DOC FF-1 ―pill test‖
(CPSC 16 CFR, Part 1630) are permitted in any area
where Class II materials are required.
I would request an article reference in 30 years of doing this that is new to me?
804.4.1 Minimum critical radiant flux. Interior floor finish
and floor covering materials in exit enclosures, exit passageways
and corridors shall not be less than Class I in
Groups I-1, I-2 and I-3 and not less than Class II in Groups
A, B, E, H, I-4, M, R-1, R-2 and S. In all areas, floor covering
materials shall comply with the DOCFF-1 ―pill test‖
(CPSC 16 CFR, Part 1630).
Exception: Where a building is equipped throughout
with an automatic sprinkler system in accordance with
Section 903.3.1.1 or 903.3.1.2, Class II materials are permitted
in any area where Class I materials are required,
and materials complying with the DOC FF-1 ―pill test‖
(CPSC 16 CFR, Part 1630) are permitted in any area
where Class II materials are required.
I would request an article reference in 30 years of doing this that is new to me?
Markl_AHC
Member
Like a number of things, there are a couple pieces needed to arrive at an answer. Run into this in every class and is similar to the discussion over clearance vs. undercut. Chapter 4 references are listed in this order so it hopefully addresses the question in a logical manner. You can really wander into the weeds on this one...
4.8.2.1 and 4.8.2.2 (already provided in this thread) - Sill refers to a part of the building floor structure under an opening and not a threshold, transition strip, etc... Annex A provides a nice drawing to help clarify this and give some context for application of the standard. Doesn't really answer your question, but important to the context of what can/should be under a door. The language was greatly improved with the 2013 edition, but sadly was not adjusted in the two references below which creates a little confusion due to the use of the word "sill".
4.8.5.1 Combustible floor coverings shall be permitted to extend through openings required to be protected by 11⁄2-hour, 1-hour, or 3⁄4-hour rated fire protection fire door assemblies without a sill where they have a minimum critical radiant flux of 0.22 W/cm2 in accordance with NFPA 253, Standard Method of Test for Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy Source.
4.8.2.13* For swinging doors with builders hardware, horizontally sliding doors, and special purpose horizontally sliding accordion or folding doors, raised noncombustible sills or thresholds shall be permitted wherever combustible floor coverings are contemplated or are in use on one or both sides of the door openings.
Here is where my opinion regarding application begins... Typically a transition strip is considered a part of the floor covering 'system'. Therefore, 4.8.5.1 would apply to the transition strip, if placed under the door, since that could be considered a part of the floor covering extending through the opening. One could make the argument (based on other Chapter 4 references) that the transition strip would need to be placed within 2" on either side of the door for NFPA 80 to apply vs. the floor covering reference in the building code. If the transition strip does not/cannot comply with 4.8.5.1, then 4.8.2.13 would allow for an appropriate solution.
Take note that this only applies to 45-90 minute rated openings. 20-minute and 180-minute are different.
4.8.2.1 and 4.8.2.2 (already provided in this thread) - Sill refers to a part of the building floor structure under an opening and not a threshold, transition strip, etc... Annex A provides a nice drawing to help clarify this and give some context for application of the standard. Doesn't really answer your question, but important to the context of what can/should be under a door. The language was greatly improved with the 2013 edition, but sadly was not adjusted in the two references below which creates a little confusion due to the use of the word "sill".
4.8.5.1 Combustible floor coverings shall be permitted to extend through openings required to be protected by 11⁄2-hour, 1-hour, or 3⁄4-hour rated fire protection fire door assemblies without a sill where they have a minimum critical radiant flux of 0.22 W/cm2 in accordance with NFPA 253, Standard Method of Test for Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy Source.
4.8.2.13* For swinging doors with builders hardware, horizontally sliding doors, and special purpose horizontally sliding accordion or folding doors, raised noncombustible sills or thresholds shall be permitted wherever combustible floor coverings are contemplated or are in use on one or both sides of the door openings.
Here is where my opinion regarding application begins... Typically a transition strip is considered a part of the floor covering 'system'. Therefore, 4.8.5.1 would apply to the transition strip, if placed under the door, since that could be considered a part of the floor covering extending through the opening. One could make the argument (based on other Chapter 4 references) that the transition strip would need to be placed within 2" on either side of the door for NFPA 80 to apply vs. the floor covering reference in the building code. If the transition strip does not/cannot comply with 4.8.5.1, then 4.8.2.13 would allow for an appropriate solution.
Take note that this only applies to 45-90 minute rated openings. 20-minute and 180-minute are different.