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I have a project involving an outdoor dust collector. My firm specified a dry-pipe sprinkler system for it.
The contractor asked if an antifreeze loop would be acceptable as a substitute, and we said no, as the AHJ does not want to deal with the maintenance side of an antifreeze loop long term. The contractor states that the head connection in the collector is pendent instead of upright, and they can't go with the dry system because of trapped water concerns. I think a dry pendant sprinkler would work as it's allowed (even required if an upright is not used) by FM Data Sheet 2.0. Anyone install a dry pendent in a dust collector, and have any drainage issues or had to add a drum drip or other means of drainage to make the system work long term? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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I have a hotel building that requires a standpipe in each of the two staircases. One of the stair shafts has a door to the outside at grade level, but there is no door to the first level inside. The lowest level with an interior door is the second floor, which has its own hose connection.
It doesn't make sense to provide a hose connection at the ground floor, but is there a code basis to support this? Thanks! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does anyone have experience with bench testing pressure-reducing FHV's?
We have horizontal corridors in a hospital, and having a fire hose and flow noise/water in certain areas is not an option. NFPA 25 2020 Edition, A.13.5.2.2 allows bench testing (i.e. remove the FHV, take it outside to conduct the 5-year test). Has anyone performed this? What is the procedure, and did the AHJ find it acceptable? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Good morning, I'm designing sprinklers for a Class III warehouse. The warehouse has a ridge vent that's currently enclosed on the side walls.
What ceiling height should be considered for the design: the average ceiling height or the height of the center of the ridge vent? The lower part of the ridge vent is 39.66 ft, and the upper part is 41.5 ft. If I consider 39.6 ft as the height, I could work with a 25.2 kPa sprinkler at 25 psi, but if I consider 41.5 ft, I should consider a pressure of 40 psi, and the fire pump would change. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe My coworker and I are disagreeing about townhomes.
Can each townhouse (3 total) have its own NFPA 13D system? Or do they need to have one total system? Each townhouse has a 1-hr separation in the form of UL U347. I cannot find anything that says they can't each have their own, but he is saying he can't find anything to say they can, to which I have always said if it doesn't say no, then it's usually allowed. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hello everyone, I’m dealing with a fire sprinkler system installed after 1984 that uses the sprinkler model shown below. I need to replace the sprinklers without changing the system’s overall characteristics. Unfortunately, I can’t find the original datasheet for this model. I can test the activation temperature and the K-factor, but I’m unsure whether this sprinkler is of the conventional type. Could anyone help me confirm if it’s a conventional sprinkler or provide any technical information about it? Thank you in advance for your help! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  We have a church with a raised platform (wood construction) that is not accessible and is a concealed space. We typically have not provided sprinklers for this type of space. The AHJ is stating sprinklers are required per NFPA 13.
Are sprinklers required for a combustible, concealed space below a raised platform? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hello, I am trying to figure out what commodity classification vinyl doors are.
I am designing a fire sprinkler system for a warehouse that stores doors and windows with the main materials being wood, glass, and vinyl. Doing a google search vinyl doors are typically made out of PVC (polyvinyl chloride). NFPA 13 - 2019 - Table A.20.4(b) lists the following: PVC (polyvinyl chloride) products, up to 20 percent plasticizer - Class III PVC (polyvinyl chloride) products, greater than 20 percent plasticizer - Group A Nonexpanded Table A.20.4.3 Examples of Class III Commodities has Furniture; wood (doors, windows, cabinets, etc.); So I'm thinking the next question that I need to ask is how much plasticizer is used in vinyl doors? I'm thinking it is less than 20% and use Class III. Any thoughts? Thank you! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I'm working with a not-so-good flow test on a project that will require a pump because of the flow test.
Where this is getting in the muck is the test flow rate being 712 gpm. The hydrant is about 565 feet from the entry and about 4 feet below finished floor elevation. This is a 5-story, light hazard with 2 standpipes, so the standpipe demand is 750 gpm. Flow test had 44 psi static and 34 psi residual with a 0.9 coefficient through the 2.5" outlet. As you know this is a 750 gpm system demand. The person over me is adamant that we not separate the sprinkler and standpipe systems out - sprinklers and then standpipe - by code when it comes to fire pumps. Even though this is a low-rise building and all we are technically concerned with is an automatic sprinkler system, and if the responding FD has an engine/pumper, the manual standpipe is in their realm. The argument is that they don't want a "partially automatic system" on any project; if a fire pump is to be provided for the project, they insist that the standpipe system connected to it must also be automatic. Back to the 750 gpm thing. At 34 psi, we have 712 gpm, obviously. The thing here is putting a 111 psi, 750 gpm pump on. They're concerned with the NPSH of the pump and not the duty point or the 150% rated test goals. (1) When a fire pump is provided to meet the needs of the sprinkler system, are the standpipes required to be automatic? (2) Is there a requirement here for automatic standpipes that I'm missing? The local jurisdiction has no amendments that affect standpipe requirements different than the model IBC. (3) Is an automatic standpipe here even achievable given the limits of the water supply, or are we causing more issues in testing down the road? If it was local, the FMs have already told me that's close enough and we will make up any flow from our trucks. What am I missing here? I understand clearly that at 20 psi the flow is 1,124 gpm. That's not what I'm trying to accomplish. I am attempting to make the combined system fully automatic per policy at 750 gpm and I'm told it's all good to go. Help a man at wit's end out here. TLDR: How would you approach manual vs. automatic standpipes when a fire pump is provided for a 5-story sprinkler system, but a 750 gpm pump could overtax the water supply? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Throughout my career, I have heard the term "turn the heads up for temporary protection during construction."
I've had bosses require uprights to be installed, and I've had bosses who just use the existing pendents and literally just turn the heads up. Which is correct? Would the length of construction determine it? How have others done this? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe How does the main drain test differ from the hydrant flow test in analyzing a water supply?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Standpipe hydraulic placards - are they required? You don’t see too many of them, so it would be difficult to find out how much psi max to pump in I don’t see many at the FDCs. Some fire marshals ask for one, others do not. I feel I’m the only one providing them. NFPA 14 6.8 requires them and tells you what to put on them (2016 to present). I place them at the exterior FDCs, base of standpipes, at the tested valves, and at the fire pump. Why aren’t the signs enforced? Are you seeing these regularly? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  Does NFPA provide guidance on campus-style fire pump design?
Can I provide two water services (one from each building) and serve out to two buildings? NFPA 20 4.9 implies that campus-style designs are acceptable, but I am not seeing any code lines referencing any further requirements for such a design. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I am working on an NFPA 13 hotel where the most demanding guest room is protected by 3 sprinklers: 1 sidewall (16x20) and 1 pendent (14x14) in the guest space, which totals 275 ft², and 1 pendent (14x14) in the bathroom. If the room meets all the requirements for the room design method, am I required to pick up a 4th sprinkler from the corridor? If not, then based on Section 19.4.1.3, would the sidewall sprinkler be allowed to use the listed flow, as the room area divided by 2 sprinklers would be less in this case? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  I am working in a warehouse with an existing ESFR system at the ceiling level. The new tenant is going to have manufacturing occupancies below, with no high-piled storage. We are utilizing the 2025 edition of NFPA 13.
There is a lot of ductwork being added to the spaces, and a question has come up regarding round and square ducts between 24 and 48" wide/diameter, and if protection is required below. For example, there is a series of (5) 42" Ø fabric ducts (Ductsox) running across a space. The top of the ductwork is approximately 6' below the deflectors of the 16.8K ESFR sprinklers overhead. When looking at section 14.2.10.3.4, I am interpreting the rules as follows - If a fixed obstruction is larger than 24" wide, and it isn't placed in accordance with table 14.2.10.2.1(a), it will require supplemental sprinklers regardless of the distance below the ESFR sprinklers. Obstructions over 48" will still always require supplemental sprinklers, and obstructions less than 24" won't need supplemental sprinklers if they can comply with one of the options 2-6 in 14.2.10.3.4. The confusion comes in with the reference to Table 14.2.10.2.1(a). Others in my office are interpreting the rules to mean that since the obstruction is greater than 31" below the deflectors, it would be acceptable to omit supplemental sprinklers underneath. I am of the belief that Table 14.2.10.2.1(a) doesn't apply at all since the obstruction is greater than 31" down from the deflectors - Since they don't comply with any of the other options in 14.2.10.3.4, supplemental sprinklers should be installed below obstructions between 24" and 48" wide when spaced more than 31" below the deflectors. What is your take on this? Are sprinklers required for obstructions between 24-48" wide when more than 31" below the deflectors? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When a new fire pump controller is installed or replaced, is an acceptance test required?
I suppose I know the answer, but I am looking for a code basis. Thank you. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Assuming a jurisdiction requires sprinkler pipe to be bonded to the building grounding system, would a sprinkler system fed from a fire pump be considered bonded since it is attached to the pump which is already grounded?
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe In sub-grade parking garages, with PRV fire hose valves/floor controls - for testing purposes, would you connect a PRV fire hose valve to the express drain via hose and pump vertically to get to the exterior grade to discharge? Are there any issues with this method during testing to consider? PRV floor control would be hard piped to the express drain and utilize the same pathway to the exterior. Then at the bottom of the express drain has a ball valve, acting as an auxiliary drain only. It can discharge to a gravity drain system, whether storm or sanitary, whatever your local AHJ permits. Or is everyone trying to discharge into a gravity drain at the bottom of the stairs and hoping to not flood anything? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  What is your method for determining whether to use a tree, looped, or gridded sprinkler system?
I would think that in most cases, a tree-shaped layout is sufficient, but I'm curious to your take as to why you'd choose otherwise. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Have 5 stories of parking with about 15 levels of residential floors above. For an enclosed, heated/conditioned garage we can use a wet system.
If we're using Extra Hazard Group 2 with high temp sprinklers or 11.2k sprinklers, which reduces our design area we know we need to account for "0.40 gpm/sqft x 2,000 sq.ft. = 800 gpm demand" at least. A PRV floor control valve like a 2-1/2" Zurn ZW5004 tops out at 500 gpm per the data sheet. Would it be possible to utilize two of these floor controls from different stairs and have an interconnected system on those levels? Or would it be better to utilize to try and separate the garage level sprinkler system from the standpipe for those levels and use a master pressure reducing valve station on ground level to feed the 5 garage levels? Would a redundant pressure reducing valve at a master pressure reducing valve station be necessary if the sprinkler feed is separated from the standpipe feed for those levels? Or could I just use a grooved 6" pilot-operated PRV like a Cla-Val 90G-21 (listed for 1763 gpm) before a floor control on garage levels? (a combined sprinkler/standpipe configuration) Lots to this, appreciate the feedback in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When calculating overhead systems with in-rack sprinklers, how much in-rack demand is added to the calculations?
I assume all in-racks within the most remote area, but want to ask to be sure I'm getting this right. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe As an AHJ, I would like to ask what other AHJ's enforce for sprinklers in R-3 Occupancies when home health or Boarding Care businesses open facilities in single-family homes?
Please explain your reasoning as well as thresholds like 5 or more, etc. We're evaluating what our requirements and/or enforcement should be. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe TL;DR:
How can surge/water hammer forces be managed in very tall high-rise fire protection system using a single high-pressure pump (~365 psi) without exceeding equipment ratings or NFPA limits? Question: Trying to pre-plan in my mind for some upcoming pretty tall highrises where design teams would like to utilize 1 pump in lieu of a high/low multi-pump set up. I'm coming up with a couple of challenges. For the sake of the problem lets assume the static pressure at the fire pump discharge flange is 365 psi. I'm concerned that fire pump starting methods might create shockwaves/water hammer in high-pressure standpipes whether it be at the start of the pump like across-the-line or end of the curve spike like a wye-delta closed might see. How concerning is creating surge forces that exceed coupling/PRV valve/Pressure Relief Valve listed ratings? First reaction for many like me has always been to utilize soft-start but electrically with generators soft-start has a much higher load that has to be accounted for in the generator sizing because of the electrical engineers have to size them as across-the-line because of the bypass & 600% FLA. Maybe they just have to suffer on their design for FPs to be what it needs to be, but am trying to be accommodating where it makes sense. Is the general method to rely on a main relief valve in these high-pressure systems? NFPA 14 limits us to 400 psi but I'm not finding pressure relief valves that are listed high enough for the static pressure of the system i.e. cal-val at 300 psi, Victaulic at 350 psi. Is anyone utilizing anything like an Amtrol Surge-Trol Tank type products? Maybe VFD controllers to flatten/lower the static pressure? Some additional concerns in my mind are PRV hose valves have a 400 psi rated value and some couplings for example Victaulic might be rated at 365 psi. I know there are higher rated couplings on the market, like 500 psi, but if my static pressure on the system is 365 psi, I could see a surge force exceeding the rated values (zero math to support that claim). I'm struggling to quantify the possible surge force values in the design phase and how to handle that. Reading SFPE Handbook of Fire Protection Engineering 5th edition Water Hammer section pg 1407, it's focused mostly on the closing of valves, and still wrapping my head around if those equations can be applicable/same for pump starting forces. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I'm working on an office fit-up, which is being fed from a dry system in an industrial facility.
I've already talked to them about providing a wet system, but that is not what they want to do. So, we've got a dry system feeding pendent sprinklers coming down to an acoustic ceiling. When using pendents on a dry system, we need to provide return bends. Does a return bend have to be for only one sprinkler, or could there be multiple heads on a single return bend? I'm picturing the pipe extending up from the main, then across horizontally, with multiple drops coming off of the horizontal. Is this an allowed approach? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe When hanging a 6-inch Schedule 10 pipe via trapeze hangers, the trapeze material is a 2.5-inch Schedule 40 pipe spanning 6 feet 6 inches. I’ve been instructed to use 3/8 rod and beam clamps for the trapeze hangers and then a heavy-duty 2.5-inch ring with a 1/2 button going down to the 6-inch pipe. The job is based on NFPA 2019. The table for NFPA 13 17.2.1.1 states that rods must be 1/2 for 6-inch pipe. I’ve been instructed that we are basing our decision on the following rule, which means we do not need to use a 1/2inch rod for the trapeze hangers themselves, only for going from the trapeze to the 6-inch pipe. 17.2.1.2 Rods of smaller diameters than indicated in Table 17.2.1.1 shall be permitted where the hanger assembly has been tested and listed by a testing laboratory and installed within the limits of pipe sizes expressed in individual listings. Is this correct? Is 3/8-inch rod or 1/2-inch rod appropriate here? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe  |
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