Window Sprinklers in lieu of Barrier for Escalator?

11/26/2020

I have a question about protection of sprinklers in windows specifically for a connection of a basement parking garage and a first level mall commercial space.

NFPA 101 accepts that there is a connection between both occupancies, but there must be compartmentalization of 3-hours without automatic sprinklers and 2-hours with automatic sprinklers. In this case, we have an escalator from the basement up to level 1, as shown below:

Can we consider this to be compartmentalized with glass and sprinklers on both sides of the glass?

Do the access doors have to be 1-1/2 hour, our could they not have any fire resistance if I have sprinklers on both sides?

This project is under NFPA 101 (specifically Table 6.1.14.4.1 for separation between occupancies), NFPA 5000, and NFPA 13 (9.3.5/19.4.3 for sprinkler protection of windows).

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2 Comments

Franck

11/27/2020 01:38:59 am

It may depends on the AHJ if he recognizes that the sprinkler protection can act as a 1h fire barrier (if the parking is fully sprinkler protected, the 2h requirement can be reduced to 1h, see § 5.2.2 below).

In that case, you can apply NFPA 13 §9.3.5 for spacing and location of sprinklers (figure A 9.3.5 is quite helpful) and 19.4.3 for the design of your water curtain (to be installed at the lower level, in your parking area).
Many insurance companies won't as a fire barrier is a passive protection, while the sprinkler protection is an active protection that may be impaired (have an impact on the PML - Probable Maximum Loss / MFL - Maximum Foresseable Loss).

If you check NFPA 88A (Standard for Parking Structures), it is indicated the following for compartmentation:

5.2 Compartmentation.
5.2.1
Those parts of parking structures located within, immediately below, attached to, or less than 3 m (10 ft) from a building or another occupancy used for any other purpose shall be separated by walls, partitions, floors, or floor–ceiling assemblies having fire resistance ratings of not less than 2 hours, unless otherwise permitted by 5.2.3.

5.2.2
The 2-hour fire resistance rating required in 5.2.1 shall be permitted to be reduced to 1 hour where the parking structure is protected throughout by an approved automatic sprinkler system.

5.2.3
No fire-rated separation shall be required when parts of a parking structure and a building used for any other purpose are separated by 3 m (10 ft) or more, and are attached only via open pedestrian balconies or bridges, or open vehicle bridges.

Franck Orset

11/27/2020 01:43:36 am

Be anyway careful with the sprinkler protection of the parking structure.
The OH Gr 1 density is somehow very optimistic and might change to an Extra Hazard occupancy in the very next future.

According to NFPA 13 (2019 Edition), parking structures should be protected as an Ordinary Hazard Group 1 occupancy, with a density of 6 mm/min over 186 m2 (0.15 gpm/sq ft over 2000 sq ft) for a wet system, or over 242 m2 (2600 sq ft) for a dry system.
This was based on the way vehicles were constructed until the 80’s, with a major use of metal components.
Because of major changes in the composition of modern vehicles, the hazard exposure has completely changed.
The transition began in the 1960s on the vehicle interior, as softer materials and padded dashboards were desired over steel dash panels for crash protection.
Main difference are:
- Extensive use of electronic components, increasing the combustible load with wiring and electronic components
- Use of plastic parts for the vehicle body, to gain weight, for better corrosion resistance or for people safety, such as the front and back ends (bumpers) that used to be made of metal and are now made (since the 19710s) of expanded plastic foams (urethane) and plastic.
- Use of plastic fuel tanks - now standard on about 80 percent of vehicles – that can melt when exposed to a fire, and then rupture and send the entire gasoline content to the ground, contributing to a combustible/flammable liquid spill pool fire.

Modern vehicles are now composed of about 50 percent plastic by volume, even though plastics account for only 10 percent of the average vehicle’s weight.

In addition, there is a growing concern with alternative fuels such as CNG, LNG, LPG or hydrogen, that present potential for explosion hazards (BLEVE effect) when exposed in a fire event, and electric car with the use of lithium-ion batteries that present an additional fire hazard and ignition source.

A typical garage fire today is much more likely to involve multiple vehicles than two decades ago. In addition, fires are burning with more severity and are much harder to extinguish.

A study made in, France showed that in garage fires between 1995 and 1997, 98 percent involved fewer than four vehicles; only 1 percent of fires involved more than five vehicles, and none of the fires reviewed involved more than seven vehicles.
By contrast, 8 percent of the garage fires between 2010 and 2014 involved more than five vehicles, and 6 percent involved more than seven vehicles.

The same study showed that in 1997, 95 percent of garage fires analyzed were extinguished in under 60 minutes. However, in French garage fires occurring between 2010 and 2014, only 40 percent were extinguished in under an hour; 30 percent of the fires took more than two hours to extinguish, and 10 percent took more than four hours.
By contrast, fewer than 1 percent the 1997 fires took longer than two hours to put out.

There is an excellent article in NFPA journal - 2019 March/April issue – Ramp Risk

You can also look at the following event that took place in 2017 in the UK (the parking was not sprinkler protected, but was an open parking structure that is not required to be sprinklered by NFPA 88A).
https://www.nfpa.org/News-and-Research/Publications-and-media/NFPA-Journal/2019/March-April-2019/Features/Protecting-Parking-Garages

https://www.bbc.com/news/uk-england-merseyside-46290095

Window Sprinklers in lieu of Barrier for Escalator?

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