Many sprinkler systems in our area (I'm a fire marshal) have aboveground pipe installed by a fire sprinkler installer and the underground installed by an underground pipe contractor. NFPA 24 requires a minimum flow rate from underground pipe in order to remove rock and debris from the underground pipe.

Many of the underground contractors simply open up the pipe and wait until there's consistent clear water and/or stop hearing the rocks ping around. There's no measurements taken for the underground flushing and when I ask for them to verify the flow rate I get blank stares.

Is there a way to tell just by static pressure in the area if opening up the pipe flange is enough flow to satisfy the underground flushing? Or is there a measurement I should be seeing to verify the flow rate? 

Thanks in advance.

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​E&O insurance; Many recognized brand names cover fire sprinkler layout, which is a re-branding of basic liability coverage for sprinkler installation contractors. The same policies will in most cases cover fire protection engineering design in instances of design-build contracts.

Does anyone know of a good underwriter of E&O policies exclusively for Fire Protection Engineering? One that is affordable, and also has a good claims payment history, S&P rating?

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We're designing a fire sprinkler system for plastic (Group A material, unexpanded polyethylene) recycling site. We are designing only for the depot area. There are raw materials stored as solid blocks up to ...We've raw material stored as solid blocks up to 12 feet (3.6 meters).

I am thinking this should be considered rack storage under NFPA 13 Section 16.2.1.2 (2016 Edition) for Protection Criteria for Rack Storage of Class I Through Class IV Commodities Stored Up to 12-ft (3.7m) in Height.

Am I wrong considering this? Note that compacted material will have a lower combustion propagation velocity than generic goods. Any ideas? Thanks in advance.

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We have a new 3,300 square foot dental facility that is single story with a basement. Is a fire sprinkler system required?

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NFPA 13 (2010 Edition) 21.23 Cleanrooms: 21.23.1.1 Automatic sprinklers for cleanrooms or clean zones shall be hydraulically designed for a density of .20 gpm/sqft over a design area of 3000 sqft.We have a wet pipe system utilizing quick-response sprinklers.

With an ordinary hazard density (.20 gpm/sqft) would I be allowed to use the quick-response design area reduction in Chapter 11?

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I need an answer for a simple question. I am working on a large airport project expansion. I have a structure of 4 levels with 70+ sprinkler zones.

Is there an NFPA standard requirement stating that each area requires a hydraulic calculation on each system?

Each system is not prototypical.

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Good morning, I have a project with a 60MVA outdoor transformer. We have a deluge valve system with wet pilot trim. 

Is there a standard requirement for protecting the transformer regarding k-factor, coverage area, and distances for a sprinkler/nozzle from the transformer?  

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Does anyone have much experience with fire pins/plugs as part of a fire door?

I came across some during a project to replace fire doors. There's a male and female component but ultimately a pin/plug is released at high temperature and goes into a hole to secure a pair of fire rated double doors.

My question is: are the pins just a substitute for a lower latch or is there some special code or regulatory driver for them?

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I have a question that stems from NFPA 318 (Protection of Semiconductor Fabrication Facilities), Chapter 11, Section 11.1.4.2.


11.1.4.2* Automatic sprinklers for cleanrooms or clean zones shall be installed in accordance with NFPA 13, and shall be
hydraulically designed for a density of 8.15 L/min·m2 (0.20 gpm/ft2) over a design area of 278.8 m2 (3000 ft2).

For a clean room 11.1.4.2 mentions 0.20 gpm/sqft density over 3,000 sqft design area. We're considering quick-response standard-spray sprinkler coverage under section 11.1.4.4. The client is requiring a double-interlock pre-action system, so under NFPA 13 11.2.3.2.5 the remote area must be increased by 30% without revising the density. 

Can we omit the 30% increase in sprinkler operation under NFPA 13 11.2.3.2.3 since we are using quick response sprinklers?

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I’m working in the construction of 4-star hotel. The water storage tank is underground made from concrete and the pump room is located above the water tank. The designer specified the fire pumps to be vertical split-case type! In order to follow code, I proposed to install vertical turbine pumps instead of the specified vertical-split case.

The supervisor Engineer is insisting to follow the specification of the fire pump and pushing me to create an underground pump room in order to install the specified pump set.

Any recommendations to avoid this directive?

I have a bad flooding experiences with this this type of subgrade pump rooms.

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​A parking garage has multiple levels covered by a dry system.

If the floor area of each level is equal to 52,000sf, is it acceptable to protect all levels with one dry system riser?

I am referencing the NFPA 13-2016 Handbook Sections 8.2 and its accompanying explanations. Thanks.

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I recently investigated some fire doors at one of our older buildings and saw they have an FM Approved label on them instead of a common UL Listing. I'm used to the UL listing label which clearly states the fire rating in minutes or hours. The FM label I saw gives some outdated ASTM standards and references a CABO report but doesn't clearly state the fire rating.

Does anyone have experience with the FM Approved fire door labels?

Based on my research, FM stopped approving fire doors a while ago. Thanks in advance.

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Indicating valve (Butterfly vs Gate Valve) Requirement in Fire Water Mains:

NFPA 24, Section A.3.3.17.1 (Edition 2019), suggests to use OS&Y gate valves, butterfly valves, and underground gate valves with post indicators.

I understand that any type of valve are acceptable to use and I've seen frequent use of butterfly and gate valves in underground main. OS&Y requirement is quite clear.

Based on my understanding, butterfly valves are less prone to corrosion and ferritic buildup when compared to gate valves due to its body design.

My understand is that gate valves, due to buildup, might be prevented from closing and would require an entire systems or section of a system to do any maintenance. Yet, direct-buried gate valves are still preferred for underground mains and I'm not sure why.

The cost difference does is not enough in my case to use gate valves specially for 8", 10" 14" or higher sizes.

Is there some reason for gate valve preferences over butterfly valves?

If a butterfly is used I could possibly see a pit being required for maintenance, but NFPA standards do not address pit requirements for a butterfly valve.

Is there any other consideration would be helpful to consider when using butterfly vs gate valves, for underground or even aboveground applications?

Any suggestions would be much appreciated.

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Have a situation I've never crossed before: we have a very small building that's getting expanded. Originally the sprinkler contractor gave two options for the general contractor to price their underground fire sprinkler service - (1) is to provide a 2-1/2" main, the other (2) is to provide fire barriers in certain areas with automatic door closers to allow the room design method be used, and bring in a 2" underground.

I completely recognize that small underground pipe is not good practice and limits the future potential of the building. We recommended a 4-inch underground, but the increased cost for tap fees and underground pricing added $10-15,000 to the job which the owner adamantly refused.

We were given notice to proceed with 2-1/2" underground and thus provided a 2-1/2" riser and 2-1/2" mains. 

The GC gave a different direction for the underground and pulled 2" underground and is providing fire barriers and automatic door closers.

We've recalculated using the room design method and everything still works with the 2" underground, but the 2-1/2" riser and 2-1/2" main is already ordered and on the way to the jobsite.

Does NFPA 13 have any restriction against having a larger riser or main size than the underground?

Because of the change in building construction, we only need a 2" riser and 2" main but will instead already have prefabricated 2-1/2" in both. My thought is to have a permanent placard clearly affixed to the riser showing the situation and clearly identify on as-builts the methodology used.

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We have an auditorium with a stage area. The stage area is fully sprinklered and provided with four natural smoke vents at the roof.

Below the smoke vents at a depth of almost 10-feet (3 meters) there is structural steel frame (provided for structural stability) arranged with narrow gap of only about 1-inch (30 mm) and obstructing all the smoke vents. We understand this steel frames will deflect the smoke plume and affect the performance of smoke vents.

Is there a standard/code reference regarding how to include this obstruction in the calculations and to prove to AHJ that the smoke vents would still be sufficient?

Thanks in advance.

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NFPA 24, Section 7.1.1.2 (2016 Edition), states that control valve shall be installed in each hydrant connection.

What is the purpose of this control valve, other than facilitating maintenance?

Would this be considered a "control valve" per NFPA 24 3.3.3, and does this have to be a post-indicating type valve?

I have a covered mall under 30' tall that requires hose valve connections in accordance with the International Building Code, Section 905.3.3.

Do these hose valve connections count as a standpipe that requires a monitored isolation valve as per NFPA 14 6.3.2?

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Should return air duct smoke detectors associated with a fan system close only the associated damper and shutdown the fan or close all dampers on the system (including supply return spill and outside air)?

How should outside air and spill air fire smoke dampers be controlled? Should these to be controlled by fire alarm?

Thanks in advance.

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When performing hydraulic calcs for NFPA 13 residential occupancies, what is the best approach to address small Ordinary Hazard rooms, such as janitor's closets or laundry rooms located on an otherwise-residential floor?

Room design is not always an option due to the prerequisites listed in NFPA 13, but area/density seems excessive when the calculation method given for residential occupancies is the 4 most demanding adjacent heads.

A 1,500 square foot area seems to go well beyond this approach, defeating the purpose of the residential design method. Other than room design, is there a justifiable code basis for calculating only the heads in the most demanding ordinary hazard room on such a floor?

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We are having a discussion in our office; we are doing a 14,000 square foot addition. The existing riser has 2 systems that are approximately 40,000 square foot each. On the middle of one of the systems there is a dry system for the loading dock.

Does the dry system count as its own system or is it included in the 40,000 square feet for purposes of a total system area?

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This week is the third of our 2020 PE Prep Series - it's 20-weeks worth of mini Fire Protection PE Exams. 

Each week we'll post the leaderboard here with the results of that week's exams. To see full leadership board and more details, visit the PE Prep Series page here.
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I am working on a project with an attic. The pitch of the attic is 12:12 and the structure is combustible construction. The area is being used as a mechanical room so the fire sprinkler layout will be Ordinary Hazard Group 1 and a wet system will protect the space since the temperature will be maintained above 40ºF. Standard spray sprinklers are being utilized because Attic sprinklers are only listed for Light Hazard use.

Using a quick response area reduction, the remote area will be 1,500ft² (OH1) x 1.3 (30% pitch increase) x 0.6 (40% quick response decrease) = 1,170ft².

Since the sprinklers are spaced along the 12:12 pitch, the floor area in plan view is substantially less than the square footage being protected along this steep slope which picks up a ton of sprinklers when I draw my remote area based on the floor. I can't find any guidance in NFPA 13 about remote area on a slope besides the typical 1.2 x √RA split between sprinklers.

Should the 1,170ft² remote area be measured based on the coverage of the sprinkler along the slope (as the protection is spaced) or should the remote area be based on the floor even though it picks up way more sprinklers than 1,170ft² of actual coverage based on the slope?

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