When a wired glass is required to have 1.5 hour fire-protection rating on a door closure, can one layer of 45 minutes wired glass be installed on each opposite side of the door to achieve 1.5 hour fire-protection rating using component additive method?
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Multi-layer wired glass fire-resistance rating
- Thread starter sunyaer
- Start date
Yankee Chronicler
Registered User
I wasn't aware that wired glass provided any fire-resistance rating. That's why the area of wired glass allowed in rated fire doors is restricted.
Inspector Gadget
Registered User
Off the top of my head, it probably isn't. NFPA 80 may have something to assist. Free online access.
Paul Sweet
Sawhorse
Wired glass isn't allowed in or near doors in the US. Does Canada still allow it?
Inspector Gadget
Registered User
It's not allowed in lieu of safety glass, or where safety glass is required. So it can be used in doors, but not where the area/height is enough to trigger safety glass requirements.
Yankee Chronicler
Registered User
But does it have a fire rating?
Doors are tested as an assembly. So, if the door is tested with the wired glass, then it would be part of the rated assembly. There is not a component pathway for fire doors, so the additive question makes no sense.
2021 IBC 716.2.5.4 Fire Door Frames With Transom Lights and Sidelights
Fire-protection-rated glazing shall be permitted in door frames with transom lights, sidelights or both, where a 3/4-hour fire protection rating or less is required and in 2-hour fire-resistance-rated exterior walls in accordance with Table 716.1(2). Fire door frames with transom lights, sidelights or both, installed with fire-resistance-rated glazing tested as an assembly in accordance with ASTM E119 or UL 263 shall be permitted where a fire protection rating exceeding 3/4 hour is required in accordance with Table 716.1(2).2021 IBC
716.2.5 Glazing in Fire Door Assemblies
Fire-rated glazing conforming to the opening protection requirements in Section 716.2.1 shall be permitted in fire door assemblies.716.2.5.1 Size Limitations
Fire-resistance-rated glazing shall comply with the size limitations in Section 716.2.5.1.1. Fire-protection-rated glazing shall comply with the size limitations of NFPA 80, and as provided in Section 716.2.5.1.2.
716.2.5.1.1 Fire-Resistance-Rated Glazing in Door Assemblies in Fire Walls and Fire Barriers Rated Greater Than 1 Hour
Fire-resistance-rated glazing tested to ASTM E119 or UL 263 and NFPA 252, UL 10B or UL 10C shall be permitted in fire door assemblies located in fire walls and in fire barriers in accordance with Table 716.1(2) to the maximum size tested and in accordance with their listings.
716.2.5.1.2 Fire-Protection-Rated Glazing in Door Assemblies in Fire Walls and Fire Barriers Rated Greater Than 1 Hour
Fire-protection-rated glazing shall be prohibited in fire walls and fire barriers except as provided in Sections 716.2.5.1.2.1 and 716.2.5.1.2.2.
716.2.5.1.2.1 Horizontal Exits
Fire-protection-rated glazing shall be permitted as vision panels in self-closing swinging fire door assemblies serving as horizontal exits in fire walls where limited to 100 square inches (0.065 m2).
716.2.5.1.2.2 Fire Barriers
Fire-protection-rated glazing shall be permitted in fire doors having a 11/2-hour fire protection rating intended for installation in fire barriers, where limited to 100 square inches (0.065 m2).
Yankee Chronicler
Registered User
But there are glass (or clear ceramic?) products that are tested for fire resistance by themselves, not as part of a door assembly. Those products have a fire-resistance rating -- and I'm pretty certain that wired glass isn't one of them.
That is true... but the OP was very clear that this is part of a door. Doors must be tested as an assembly. There is no way to do an additive approach via the components utilized. The assembly, inclusive of all components, must be tested as a single item via ASTM E119 or UL 263.
Yankee Chronicler
Registered User
Unless accepted by the AHJ as a modification. In doing restoration work for major universities with old "college Gothic" buildings (some genuinely historic, some just very old), I've been involved as a code consultant and gotten existing 9-panel, stile-and-rail oak doors approved as equivalent to 45-minutes for rated corridors by backing up the raised panels with a layer of 5/8" Type X GWB on the room side, thereby preserving the historic appearance of the doors on the corridor side.
Using Harmathy's principles from Resource A of the IEBC, what we find as one of the rules distills down to "If something resists fire, more of it resists fire better." It would be a gutsy call on the part of the AHJ, since adding a second layer of wired glass would void the label on the door, but it clearly wouldn't make the door any worse. The big problem with wired glass (or any glass) in a rated door is temperature rise in the glass, and having two layers with an air gap should improve that, not make it worse.
Yes, I suppose an AHJ could go that route. I would say that going that route would take a very trusting (or ignorant) BO. Sec. 104.11 requires research reports for good reason. I surely would not buy off on adding another panel of glass to a listed/tested door and take on acceptance of an increased fire resistance. I'm quite sure the original manufacturer would have no part in it as well.
Inspector Gadget
Registered User
Psst: Canadian Code question.
Whoops... yes it is. Missed that!
This is from Ontario Building Code Division B. How to interpret it? Does this not apply to window assemblies, glass block or wired glass in a door closure? (the door can be seen as the larger closure while the wired glass in the door is the smaller closure)
Yankee Chronicler
Registered User
I'm not in Canada, but I would interpret that to refer to what the IBC refers to as the "opening protective." If the opening is a doorway, the opening protective is the door, so you would be talking about using (for example) two 1-hour-label doors to protect a single opening in a 2-hour wall, or two 90-minute doors to protect an opening in a 3-hour wall.
I'm assuming that the Ontario Building Code uses "closure" to mean the same as the IBC "opening protective."
Understood.
My question and doubt now comes down to: can the the fire resistance rating of the glazing (vision panel) in a fire door use the 3.1.8.5.(1) sum rule in my last post?
Yankee Chronicler
Registered User
I don't know how it's done in Canada. In the U.S. the door assembly, with the glazing and stops in any vision panels in the door, are tested as an assembly.
tmurray
SAWHORSE
What that is speaking to is when you have an assembly where there are layers of wired glass or glass block on each side. very similar to the component additive method in concept.
Normally this is done where assemblies are thicker and the additional layer is required to maintain the continuity of the fire separation because the fire assembly must be rated from fire exposure from both sides for walls.
Likely not applicable on a door as the glass is in the same plane as the door.
Normally this is done where assemblies are thicker and the additional layer is required to maintain the continuity of the fire separation because the fire assembly must be rated from fire exposure from both sides for walls.
Likely not applicable on a door as the glass is in the same plane as the door.
What if the door is made to have twice the thickness of the wired glass?
tmurray
SAWHORSE
I'm not sure I can agree that this would apply to glazing in doors at all. That rating should be coming from what the door achieved when tested under CAN/ULC-S104.
It is arguable because normally window and glass block ratings come from CAN/ULC-S106, but there are provisions for rating under the code for wired glass and glass block as well. But I don't feel those rating provisions apply to doors.
In Canada, you cannot field modify a fire rated door at all. If you want a window in it, you order one with a window. The door had to be tested with the window in it, so the code would naturally be silent on the issue.
It is arguable because normally window and glass block ratings come from CAN/ULC-S106, but there are provisions for rating under the code for wired glass and glass block as well. But I don't feel those rating provisions apply to doors.
In Canada, you cannot field modify a fire rated door at all. If you want a window in it, you order one with a window. The door had to be tested with the window in it, so the code would naturally be silent on the issue.
Is field modification allowed for small area like vision panel?
Paul Sweet
Sawhorse
I believe the limit on glass area in a fire door is due to the radiant heat transmitted through the glass. I don't think a second layer of wired glass would block any more radiant heat and increase the fire rating.