Glazing protection

[Shredocaster]

Hello, All

With the NFPA 13, 2016 (8.15.26) and tyco shops clarifying what can and cannot be done in regards to glazing protection is there any other option for glazing protection on a set of windows with horizontal mullions? The architect's up here in my land want to use Glazing protection to cure many issues and don't seem to understand the limitations, thus I am "hunting" for any other possible remedies to help.
Thanks!

 

[cdafd]

I would say they need to start with the building code, for that project. To see if it is even allowed.


This is from IBC for atriums. An ahj might use it as alternative design??



404.6
Enclosure of atriums. Atrium spaces shall be separated from adjacent spaces by a 1-hour fire barrier constructed in accordance with Section 707 or a horizontal assembly constructed in accordance with Section 712, or both.

Exceptions:

1. A glass wall forming a smoke partition where automatic sprinklers are spaced 6 feet (1829 mm) or less along both sides of the separation wall, or on the room side only if there is not a walkway on the atrium side, and between 4 inches and 12 inches (102 mm and 305 mm) away from the glass and designed so that the entire surface of the glass is wet upon activation of the sprinkler system without obstruction. The glass shall be installed in a gasketed frame so that the framing system deflects without breaking (loading) the glass before the sprinkler system operates.
2. A glass-block wall assembly in accordance with Section 2110 and having a 3/4-hour fire protection rating.
3. The adjacent spaces of any three floors of the atrium shall not be required to be separated from the atrium where such spaces are accounted for in the design of the smoke control system.


One of the basic premises of atrium requirements is that an engineered smoke control system combined with an automatic fire sprinkler system that is properly supervised provide an adequate alternative to the fire-resistance rating of a shaft enclosure. It is also recognized that some form of a boundary is required to assist the smoke control system in containing smoke to just the atrium area. The basic requirement, therefore, is that the atrium space be separated from adjacent areas by fire barriers and horizontal assemblies having a fire-resistance rating of at least 1 hour.

Also, openings in the wall are required to be protected, in accordance with Section 707.6. In accordance with Section 708.4, shafts are required to have a fire-resistance rating of at least 2 hours if connecting more than three stories, and 1 hour when connecting two or three stories. The basis for the 1-hour requirement in Section 404.6 is that an automatic sprinkler system can be substituted for the 1 hour of fire resistance of a shaft enclosure. The allowance is consistent with the 1-hour fire-resistance-rating reduction permitted in high-rise buildings (see Section 403.2.1.2).

In lieu of a 1-hour fire-resistance-rated separation, Exception 1 allows adjacent spaces to be separated by glass walls where automatic sprinklers have been installed to protect the glass. The sprinklers are to be located so as to wet the entire surface of the glass wall. If there is a floor surface on each side of the wall, both sides of the glass must be protected. The glass must be in a gasketed frame such that the framing system can deflect without breaking the glass.

Although this exception does not address obstructions or other window treatments, consideration must be given to locating such items to avoid interference with the required sprinkler heads.

Without specific test evidence, curtain rods, traverse rods, curtains and draperies must be located at least 12 inches (305 mm) from the window surface [see Figure 404.6(1)]. Any doors through the required 1-hour fire barrier wall must be 3/4-hour rated in accordance with Table 715.4.

The sprinkler system required for Exception 1 is not intended to be a deluge system. Instead it is intended to protect the glazing material from breakage as a result of thermal shock. It is not necessary to activate all the sprinklers along the glazing material to provide such protection as long as the entire surface of the glazed panel is designed such that it can be wetted by the sprinkler system.

Exception 2 allows a glass-block wall assembly conforming to Section 2110. It is important to note that these glass-block assemblies do not require the sprinkler protection that is required by Exception 1.

Exception 3 recognizes the desire to have at least some floors open to the atrium, and permits a maximum of three. The three-floor restriction is consistent with the basic premise that the life safety hazard becomes significant when more than three floors are open and is also consistent with the allowances for covered mall buildings. It should be noted that the three floor levels may be at any height and need not be consecutive floor levels [see Figure 404.6(2)]. The exception also states that the smoke control design must account for these spaces. This particular reference to the smoke control design does not require that the 6-foot-high (1829 mm) layer required by Section 909.8.1 be maintained in these spaces. Instead it is saying that if a smoke control system is required by Section 404.5, such spaces must be accounted for in terms of the hazard they pose to the atrium and to smoke migrating to other adjacent spaces on other stories open to the atrium. Essentially these spaces have simply increased the possible design fires that may send smoke into the atrium, thus threatening to send smoke throughout the building and other adjoining spaces. If the atrium smoke control system is not designed to handle fires in these areas, the system may become overpowered. This exception can also permit a two-story atrium to have adjacent areas open to the atrium. In this case, since there is no required smoke control system, obviously there is no need to account for the added space (see IBC Interpretation No. 54-07).

As discussed in the commentary to Section 404.1, the atrium requirements are basically an exception to the shaft requirements in Section 708.2. More specifically, Section 708.2 has multiple exceptions that are all legitimate alternatives to the shaft requirements. If there are portions of the building applying other exceptions to Section 708.2 that are not separated from the atrium, they can be considered part of the atrium themselves and be subject to the smoke control layer height of 6 feet (1829 mm) or could be considered as adjacent spaces and need to be accounted for when designing the smoke control system, as discussed above. It should be noted that if the space is considered part of the atrium itself, the other exceptions in Section 708.2 need not apply as the atrium provisions are already being applied.

 

[stookeyfpe]

To your question, I am not aware of any options for the protection of glazing with sprinklers when mullions are involved. It makes sense given that the mullions are going to interrupt the distribution of the sprinkler discharge and mullions are commonly constructed of metal, which have a much higher thermal expansion coefficient compared to glass.

In my jurisdiction you would be advised to purchase the expensive fire-resistant glazing, reduce the area of glazed opening to the limits specified in the Building Code, make the wall blank, or seek professional engineering assistance in the development of an alternative method of compliance.