How do you size a water storage tank for fire flow when the city supply is significant, but not sufficient for Fire Flow?
For instance, if I have 1,500 gpm available from the city at 20 psi, but I need 2,000 gpm for Fire Flow, is the water storage tank sized for 500gpm for the required duration? Or do I need to size the tank for the entire 2,000 gpm minus reliable refill? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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Can a 4" pump with 4"-6" discharge fitting be used on a private 10" combination line (fire suppression and hydrants)?
NFPA 24 Section 13.1 states that no line less than 6" shall service a hydrant. But does the fact that NFPA 20 Section 4.16 allows the 4"-6" discharge fitting as part of the pump assembly overrule this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When are pressure reducing hose valves required on a dry automatic standpipe system?
I have a project where I have been asked to evaluate an existing sprinkler system for an 8-story apartment building. The original installation falls under NFPA 13/14/20 2013 edition. The building is served by four dry automatic standpipes and a separate wet sprinkler feed. The standpipes are not combination sprinkler/standpipes. The fire pump churn pressure is 212 psi and there is a pressure reducing valve provided for the wet system supply. There is no pressure reducing valve for the dry automatic standpipes. The hose valves on the standpipes are the pressure restricting type. Not pressure reducing. When reviewing the data sheets for the hose valves, it states "Adjustable restriction of pressures up to 175 lbs....at residual flow" but the valves themselves are rated to 300 psi. At normal, non-fire conditions, the standpipes have 23 psi static pressure of air, but if the dry valve were to trip for any reason, (non-fire or not) the standpipe exceeds 175psi static pressure on the 1st-7th floors. NFPA 14 2013 states that "7.2.3.2* Where the static pressure at a 21⁄2 in. (65 mm) hose connection exceeds 175 psi (12.1 bar), an approved pressure regulating device shall be provided to limit static and residual pressures at the outlet of the hose connection to 175 psi (12.1 bar)." Would the static pressure be considered the normal air pressure or the static pressure if the dry valve trips? My assumption here would be that the pressure restricting valve needs to be swapped for a pressure reducing type. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a canopy that is completely detached from a building (school) and is an entirely a separate structure. The canopy has no walls and is not in an egress pathway. The canopy is used for bicycle storage and bicycles are not stored overnight.
Is there any code path to require sprinklers underneath this canopy? If not, what is the code path to omit fire sprinkler protection? Thanks for your help! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Are there any universal, non-AHJ-specific requirements for permitting sprinkler alterations and/or repairs?
I have been told that “code” requires a permit to be pulled for any and all sprinkler alterations. Upon further questioning, I determined that this came from a fire marshal showing my colleague something in the IBC once, but, even if that were true, wouldn’t that still require adoption and implementation by a jurisdiction? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does a security grill utilized in school corridors required to be tied into the fire alarm?
If so, the concept should be that the grill in the closed position should return to the open position when fire alarm is activated, correct? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What is the difference between the terms "permitted" and "required" in NFPA standards?
For example, a later chapter will say that "Smokeproof enclosures complying with 7.2.3 shall be permitted.", which will point you back to: 7.2.3.1 General. "Where smokeproof enclosures are required in other sections of this Code, they shall comply with 7.2.3, unless they are approved existing smokeproof enclosures." The "parent" section uses the phrase "where 'required' elsewhere", while the occupancy-specific section uses "permitted", as in allowed to be required, without specifically requiring it. This feels very cyclic. Am I directed back to the separation requirements of Chapter 6, or is there something buried in the occupancy chapter that I am not seeing? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does any one know in 1960's and 1970's, what the flow and pressure requirements of 1-1/2 inch standpipe system hose of NFPA 14?
This would be for a Class II system. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can window sprinklers be used to protect internal glazing in partitions in lieu of fire rated glass partition?
The life safety engineer has requested to provide sprinklers on internal fully glazed partitions to save the cost of fire rated glazed partition. Not for the entire hospital, only some internal partitions in a hospital for glazing with 1-hour fire rated ones. Although couldn't find anything in the NFPA 13 that support his request as I know this is valid only for atriums, am I right? I appreciate the help and response as always. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe If you've enjoyed being part of the community and are looking to make a greater impact in the industry - consider joining up with us! We have a few part time opportunities currently open where you can earn on the side and make a greater impact in the industry. More details here:
Is there any code that requires that fire alarm coverage be provided in areas that are in the process of major modifications, including asbestos abatement work?
We have a project which will undergo major asbestos abatement and are getting pushback that the fire alarm system must remain operational in the space during the renovation work. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have seen this method of arranging fire suppression components (see attached schematic) several times where I live. The attached is a partial re-creation of the fire water entry schematic for a high-rise building with a fire pump. The system has low and high pressure zones. The underground parking dry systems are served by the municipal water directly, and the standpipes and aboveground sprinklers are fed by the pump. Questions: 1. Can you have a FDC serving the low pressure zones as shown on the suction side of the pump per NFPA-14 6.4.3.1? 2. If not, how should the schematic be arranged instead? 3. What could happen if the Low Pressure FDC were pressurized as shown? This project was built under the 2013 editions of NFPA-13, 14, and 20. I am asking because I am beginning design of a sprinkler system for a 22 story high-rise. Thanks for your help. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hi all, what is the maximum length of the connection from the hydrant to the fire water main?
NFPA 24 mentions that the minimum size is 6" but couldn't find anything related to the pipe length. Thanks Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Another month, another 20+ great discussions happening on the Forum. Thanks to all those who have contributed! Here are the Top Ten from April:
Is it code-mandated to have two control valves in the fire pump bypass piping?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What design considerations (if any) need to be taken into account for the new refrigerant changes that are coming up for the HVAC industry (slightly flammable or highly flammable refrigerants)?
Are there any code updates, guidelines reference materials etc. Would this possibly affect hazard classifications? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can anyone make sense of extended coverage sprinkler max spacing and areas to me?
Looking at NFPA 13 (2016) Table 8.8.2.1.2 or (2022) Table 11.2.2.1.2 "Protection Areas and Maximum Spacing (Extended Coverage Upright and Pendent Spray Sprinklers): In unobstructed and obstructed noncombustible construction, the max spacing is uniform for 196 square foot protection areas as 14 feet. Kinda makes sense, 14 x 14 is 196. But then when we get to 144 square foot spacing for Ordinary Hazard, we have 12'-0" maximum spacing (okay, 12 x 12 is 144); but then when we do 144 square foot protection area for extra hazard or high piled storage on this chart, you can have 15'-0" max spacing. The way I'm reading it is: If you have 12' x 12' spacing in ordinary hazard, you can use the Extended coverage pressure for 144 square feet but if you have 10' x 14' spacing, despite a smaller protection area in ordinary hazard (144 sqft vs 140 sqft) because of the 14'-0" spacing, I should calculate using the head's starting pressure for 196 square foot area of protection starting pressure. Whereas the same situation in extra hazard or high piled storage would allow me to use the 144 square foot starting pressure, as I haven't exceeded the 15'-0" maximum spacing or the 144 sqft area of protection. Just seems counter-intuitive to me. Can anyone make this make sense? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Consider a high-piled rack storage area with 30 ft roof height and the following arrangements:
(A) Class I through IV and cartoned nonexpanded Group A plastic up to full rack height (B) Exposed nonexpanded Group A plastics, only up to five feet NFPA 13 Table 23.3.1 prescribes protection criteria for (A) as pendent K25.2 at 15 psi starting pressure; however, it does not provide protection criteria for exposed nonexpanded Group A plastics using K25.2 sprinklers where ceiling height is ≤ 30 ft. NFPA 13 Table 4.3.1.7.1.1 prescribes protection criteria for (B) as Ordinary Hazard Group 2. The owner will have exposed nonexpanded Group A plastics. They have agreed in writing to maintain exposed nonexpanded Group A plastic to the bottom five feet of the racks. Would storing exposed nonexpanded Group A plastics only in the lowest five feet of the rack, with Class I-IV above to the full rack height, be permissible? If so, the overhead sprinkler design under NFPA 13-2022 § 20.4.13.2 would only require the more-demanding of the two criteria (which is A), correct? Some have suggested that the presence of the exposed nonexpanded Group A plastic within the (A) criteria mixes with the (B) criteria to form a more hazardous condition than posed by either individual commodity / arrangement. However, NFPA 13 § 20.4.13.1 and 20.4.13.2 seem to require each commodity / arrangement to be considered independently and not to hypothesize protection requirements based on commodity / arrangement mixes. Long one, but thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Typically when I work on campus/multi-building systems, I am using a single underground main and splitting off to each building. Since you don't have to consider a multiple building fire problem, we have typically worked on the hydraulically most-remote building for underground sizing and use wall PIVs to offer individual building shutoffs, with FDCs on the individual buildings.
I'm getting challenged on "what allows this in code?" It's mostly a question of - where is the limit on how long a loop can be? I'm looking at this from a sprinkler design perspective and whether each individual building's sprinkler system is able to perform hydraulically. Is the limit for the length/layout/sizing of a campus underground loop simply the more demanding of Fire Flow or sprinkler system feeds? Is there a code basis for this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe AHJ is requesting the design curve for the fire pump to be 5% lower than the pressure limiting driver (PLD) set pressure to account for the tolerance allowed NFPA 20-2019 Section 6.2.2.2 "When operating below the rated speed in a self-regulating mode, a self-regulating variable speed fire pump unit shall maintain the discharge pressure within 5 percent of the set pressure."
Is this an appropriate application for this requirement in NFPA 20? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is there a general rule of thumb concerning overall installation cost for standard coverage vs. extended coverage sprinklers?
That is, if I can use half as many extended coverage (EC) sprinklers, is the system going to cost significantly less or more? Two examples come to mind:
Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hi All, I have a two part question regarding sprinklers below ductwork exceeding 48" wide. Both areas below (in different locations) are Ordinary Hazard, 130 sqft maximum spacing. When protecting below the ductwork in the elevation sketch below, is the 6'-11" dimension doubled to be 13'-10" the same as when spacing to a wall (SxL) ? Or can the distance to the next sprinkler be 15-ft (15 x 6-11 = 103.75 sqft)? In the plan view below, are sprinklers required below the 60" wide duct ABOVE the AHU (shown in green), if the vertical distance between the AHU and bottom of duct is greater than 24"? This would be under NFPA 13-2019, Section 9.5.5.3.1.5. Many thanks!
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does anyone know of a sleeve product that can be installed AFTER pipe installation without backing out the pipe?
The underlying issue is that I have a project with seismic requirements (for extra clearance at penetrations) that has many fire rated walls. Basic pipe sleeves with extra large clearance filled with fire caulk is our typical situation, but if a sleeve gets missed during rough-in, we're hoping to use something after that fact. So either looking for a split sleeve of some type, OR a way to fire caulk a 2 hour rated gypsum wall with extra large clearance per NFPA 13-2016 section 9.3.4.3. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe A building 2,880 sqft, 20-ft in height, Type IIB with classification of 4 for occupancy hazard.
When I calculate the gallons needed for a water storage tank, is this based off a 2-hour fire flow per NFPA 1142? If so, where can I find that requirement? 2,880 sqft x 20-ft height = 57,600 cubic feet / 4 occupancy hazard x .75 = 10,800 gallons. Is this 750 GPM x 120 minutes for a total of 90,000 gallons? Huge difference between the two. Thanks. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hello everyone, I am currently working on a project where 5 deluge valves will be installed in a dedicate riser room. The room will only contain the deluge valves (5), the foam tank and air compressors.
How would you recommend I give dimensional requirements for this room to the architect? What's your thought process, or lessons learned, for sizing rooms like this? Thanks in advance - much appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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