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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
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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 In a recent project, I asked for hydrant flow test results from the civil engineer, and I received Boundary Conditions instead.
Is there a way of using this information to validate hydraulic calculations? An example of Boundary Conditions given to us: Demand = 18.54 gpm (1.17 L/s), HGL = 463'-11" (141.41 m), Pressure = 64.1 psi (442 kPa). Thanks! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have an existing manufacturing area subject to NFPA 13-2022 Edition.
The Ordinary Hazard Group 2 manufacturing area sprinkler system can meet Figure 21.2.2.3.2 requirements for 0.20 density over 2,200 SF plus 500 GPM for hose streams required for Class III storage to 20 ft. high. Does the Ordinary Hazard Group 2 requirement of Section 4.3.3.2 (2) still limit storage height to 12-ft, regardless, since this is not a dedicated storage area? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have wrote up several pump sensing line locations where they tap into the system. I understand it that they need to be be install between the discharge check and discharge control valve.
A contractor keeps installing on the pump bypass and says it works fine. Is this compliant? Is there a downside to attaching to the bypass? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I am pricing sprinklers in a steel frame building with Z-Purlins and a white vinyl backed insulation composed of inorganic glass fibers which are bonded with a thermoset resin to form a uniformly textured blanket style insulation at the Roof.
In an otherwise noncombustible area above the ceiling will the White Vinyl Backed Vapor Barrier System now make this above ceiling area combustible, requiring sprinklers? From the data sheet I have found the vapor barrier has a flame spread of 0 but have found from a google search flame spread and combustibility are not the same. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Looking to learn more about NFPA 72-2019 18.5.5.7 Performance-Based Alternative for visible notification. Currently have a single 95cd wall-mounted horn-strobe approximately centered in an club office room that is approximately 41-ft by 34-ft, ceilings at 11-ft. The is a wall on the far end that is about 10-ft and 9-ft off the back wall and full height. Table 18.5.5.5.1(a) is based off direct line of sight is my understanding, but would give a maximum room size of 50-ft x 50-ft. Are there any resources available to help understand how to quantify the that 0.0375 lumen/ft² of illumination is met from reflection of surfaces behind the wall? I'm sure there are more inputs that are needed but just looking to get started at how to attack the problem. Thanks in advance Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  Good morning! Is there any NFPA 13 prescriptive option for this type of obstruction? These are ceiling waves with a horizontal fall chain lighting system.  Thanks in advance.
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Sometimes we would not want to evacuate entire buildings in a fire alarm condition, even outside of healthcare facilities.
If a fire alarm is programmed to evacuate only "affected" areas, what defines the boundaries of the affected area? What building features are required to implement a defend-in-place strategy, in a large Industrial Facility F-1? Where can I find the specific rating requirements for the fire and smoke barriers separating "affected areas"/zones? Looking to understand this concept and the requirements around it better; thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can a branch line tee to multiple sprinklers? Please see the attached example. I'm trying to figure out if a branch line that has a tee to multiple sprinklers would then be considered a main or still part of the branch line. This question also applies to looped branch line systems.   The classification of branch lines and mains can have a major effect on the amount of seismic bracing required.
NFPA 13 defines branch lines as "The pipes supplying sprinklers, either directly or through sprigs, drops, return bends, or arm-overs." NFPA defines arm-overs as "A horizontal pipe that extends from a branch line to a single sprinkler or a sprinkler above and below a ceiling." Therefore, others that I have talked to have argued that the branch line will become a cross main since it is now feeding two sprinklers off of one line. This as a result would require additional seismic bracing. NFPA defines a cross main as "The pipes serving the branch lines, either directly or through riser nipples." In my opinion, the pipe would remain a branch line because it still aligns with the branch line definition. Moreover, there is nothing in NFPA that says that branching/teeing from a branch line automatically reclassifies the branch line as a main. Just because a pipe is no longer serving as an arm-over doesn't categorize the pipe feeding it as a main. The distinction between branch lines and cross mains is primarily based on their roles within the overall system, branch lines serve individual zones or areas, while cross mains supply multiple branch lines. What do you think? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Are air compressors for dry fire sprinkler systems required to be listed?
Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I am a President of Board of a 4-story condo building. The building was built in 1982 and is concrete block. We received permission from fire marshal several years ago to remove all our fire hoses. The fire department told us that if there was a fire they would not use them. They would hook up to the FDC in front of our building. My question is - what is the purpose of the building's fire pump, and can we petition to also have it removed?  What are the deciding factors or requirements on when a deluge system would be required on a stage to separate the stage from the audience?
This would be for the proscenium opening protection. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does code allow a fire sprinkler riser to be installed in a rated stairwell enclosure?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We really appreciate the insight and collaboration from everyone on this forum - to make it helpful, informative, truthful, and help us all do our work better to make the world a little safer & more reliable. Much appreciated. Here's the Top Contributors from March 2024:
Is "tenting" wet system piping (in an unheated attic) an appropriate approach to protect the pipes when the outside air temperature can drop to approximately 0 degrees F for multiple consecutive days?
In this case, the soffit and ridge vents allow exterior air into the attic space and there is no air barrier to prevent cold air infiltration. I have reviewed NFPA 13 and 13R and cannot find a definitive answer. Many thanks for assisting. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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