This may sound like a strange question, but here it goes.
Is there a way to downsize a fire water storage tank based on the refill rate supplied by the city? I know that in Houston there was a company that supplied calculations showing that the refill rate could supply the tank at a refill rate based on the flow test. Could anyone substantiate this principle? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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Can ESFR Be Used for Extra Hazard Group 2?
ust before I saw that discussion on the forum I was confronted with a nearly finished, similar situation. A new technical plant for manufacturing of large-diameter high voltage cables. Huge amount of PE in the next-to-outer layer, and the sprinkler designer have based the fire protection on ESFR due to ‘’all the plastics’’ and generally large ceiling heights – variation between 40 and 55 feet – and a wish for ‘’maximum flexibility’’, by using table values for UUP for the respective ceiling height. NFPA 13 – 2019 is to be used for the design. The manufacturing process starts with a thin single wire and ends in an obvious UUP commodity. In my mind this is mostly a production risk to be protected with spray sprinklers and density/area calculations, or CMSA-sprinkler parameters where the ceiling height permits it, especially as most of the fire load is moving cables, without automatic stop because the alarm could be undesirable or false. It was said that cables during production would be directed up towards the ceiling, turn and twist on large diameter wheels, and also have large horizontal stretches before they run down into the next machine that may put on a new metal screening or extruding the outer PE layer before PVC or similar outer layer. Obviously a multi-stage production that in the end makes one large cable from 3 or more smaller cables. As I have seen in earlier discussions, the understanding of the text in chapter 23.1.1 saying ‘’ESFR sprinkler shall be permitted to protect : …. Any storage arrangement OH1, OH2, EH1, and EH2 design criteria’’ must be vital for the understanding. I don’t feel the actual situation is a storage arrangement, but if so, what is the target for the wording design criteria? I suspect there will be ‘’longitudinal flue spaces’’ between the cables, transvers flue spaces are not possible. Some places there will be cable(s) in conflict with the minimum 300 mm horizontal distance from a storage suppression sprinkler rule. However, this is the first time I have been presented for a ‘’ceiling only’’ option with 1 or 2 intermediate levels ESFRs having water shields. And (luckily !?) someone had found the FM DS 8-9 Table 17b and put in K 480 storage sprinklers in the part of the manufacturing building with the highest ceiling. Hopefully this is not the only cable manufacturing plant in the world, and I would greatly appreciate other views on this subject. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have an NFPA 13 system, using residential sprinklers, in a dwelling unit that has 2-levels of smooth flat ceilings. There are two levels of ceilings (9'-0" on left, 8'-0" height on right). Image provided below: Sprinklers are hydraulically calculated at their listing with a 20 x 20 spacing, and there is not an issue providing 0.10 gpm/sqft.
See the spacing above - is this an allowable arrangement though considering how it was calculated? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Should the FDC (shown below) be connected where it is shown on the proposed riser schematic? It is my opinion that the right portion of the image below does not show proper connection of the FDC to the risers.
Is this correct? It appears that the FDC if used, would send pressure back against the RPZ and diminish fire flow to the risers in use. The pressure at the street is 80 psi. Water coming in at the FDC may be 150 psi. Note the connection to a fire hydrant. Should the FDC connect directly to the dry and wet pipe fire sprinkler risers as required by code or is the proposed riser schematic acceptable? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe So I've run into this a couple of places and I'm curious where other professionals land. You have a warehouse that has a mezzanine. Say the warehouse is 20'-0" tall and the height of the mezzanine is an even 10'-0".
You have 8'-0" of shelf storage underneath the mezzanine. You have 8'-0" of shelf storage on the mezzanine. You are protecting under the mezzanine separately, but the mezzanine does not make up the full floor area of the entire warehouse. So there are open areas where you only have 8'-0" of storage to a taller 20'-0" building. Does the storage over the mezzanine bring your storage up to 18'-0" or is it 8'-0" of storage? It's 18'-0" over the floor, but 8'-0" over the floor of the mezzanine. And there is protection beneath the mezzanine, but the storage under the mezzanine extends beyond the outline of the mezzanine. It's still only 8'-0" high, but now the ceiling height is different. Anyway, any input or thoughts would be great. Code references always appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What does "listed for fire protection use" actually mean?
The Department of Defense specifications Section 21 13 13 calls for backflow preventers to be "listed for fire protection use". From what I have found, there is no such specific listing. Has anyone else heard of this? Thank you for your input. When should sprinklers be installed on CPVC systems, before or after the drop is "glued" in place?
NFPA 13, 2016 Edition, Section 8.3.1.4 "Where solvent cement is used as the pipe and fittings bonding agent, sprinklers shall not be installed in the fittings prior to the fittings being cemented in place." From my time in the trade; about 13 years I have always seen fitters "prepping" their CPVC sprinkler drops by "gluing" the sprinkler adapter on, then tightening the sprinkler into the adapter, and then sitting the drop vertically in a bucket with the sprinkler on the top. They say that way if any glue runs down from the joint it just goes into the drop and not down in to the sprinkler itself. That is easy enough, but what about the Tee or Elbow that the drop is going to be glued in place into? Personally the way I did jobs while I was a foreman is we would pre make the drops, cut in a 1/2 to a whole floor and then run back through and install the sprinklers into the drops. Personally I liked that because I only had the sprinklers on the job the day they were getting installed, no worries about getting stolen or damaged from being on site, and then no worry about glue getting into the sprinkler at all. Plus when we went around just putting sprinklers in it was extremely fast and no hold back wrench required. And it was literally just taking that process of removing the sprinkler from the box and tightening it in to a fitting and shifting it to a different day. Plus I have personally pulled sprinklers out of CPVC systems where the head/button was filled solid with glue. The way I read Section 8.3.1.4, I take it as all the fittings, not just the particular fitting that the head is installed in to. But I definitely can see how it could be interpreted as only the fitting the head is installed in. How do you other code followers see it? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe During fire pump testing, for the churn test, should the system valve (on discharge side of course) be open or closed?
I lean towards it being open, as I would rather know the weak point during a test than during an actual fire event. Here's my pro/con list to keeping the valve open: Pros (keeping valve open)
Cons (keeping it open)
Thanks in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a project where there is a very high corridor at a high school (45-50 feet high). There are 30-inch deep steel 'I' beams spaced at around 20-ft apart.
Should this be considered obstructed or unobstructed? Should deflectors be at 1"-12" below deck, or can they be lowered to maximum of 22" below deck? Do all deflectors need to be at the same elevation? Since the beams are deeper than the deflector elevation, I'm looking at Table 8.6.5.1.2 for distances from the beam to avoid the beam with the sprinkler spray. Thank you in advance for your input. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe NFPA 1 and 13 exclude large storage containers of household goods such as those stacked within buildings by well-known brands.
We know the range of consumer plastics that should be expected within the containers. The containers themselves are made entirely of wood or of fiberglass with metal frame. They are stacked one atop another, as high as possible, inside buildings of storage occupancy. How are these hazards/commodities to be classified? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have an existing warehouse that has a overhead pipe scheduled system from the early 80's. It is all threaded schedule 40 pipe. The system schedules from 8" at the riser to 2" at the last piece off main. I ran a calculation and this existing system and it equates to Ordinary Hazard Group 2 at 0.20 gpm / 1,500 sqft. The owner has installed (4) racks sections (per plan), each one separated by 12-ft. All located in one portion of the warehouse. The fire marshal requested that they submit for a permit to confirm that the existing sprinkler system is adequate. The storage is 25-ft. (5-ft above the top of the 20-ft rack.) The ceiling is 35-ft. The commodity is Encapsulated Group A, nonexpanded plastics on wood pallets, on open shelves with a 6" flue. Plan view of storage configuration Does NFPA 13, 2019 edition, section 25.8, option 1, 2 or 3 allow me to install sprinklers only in these racks, as a stand alone design, without making modification to the overhead sprinkler system?
This may eliminate the need for the owner to upgrade the existing overhead system and install a fire pump. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe From the perspective of a responder, any thoughts on using large diameter hose on a freestanding Storz FDC versus the old 2-1/2 inch standard two-inlet threaded fire department connection?
Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hi all - I am currently reviewing an ESFR sprinkler protection of compressed, rolled-mattresses in cartons.
During a fire, once the carton burns, the mattresses will be able to retrieve, at least partially, its initial uncompressed configuration. Considering this, I'm skeptical about it being classified as a cartoned unexpanded plastic. It seems to me that the proper classification should be cartoned expanded plastics, as I've found nothing justifying this optimistic opinion. Do you have an opinion on how this should be properly classified, or how you would view it? I'd love to hear about your point of view on the subject and choices made for similar projects. Thanks and regards. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a 6-story condo building. It's an NFPA 13 system on the first floor, and NFPA 13D with PVC piping above.
Over the years this building has had leaking sprinklers. The last two leaks were within a week of each other, one in the second floor laundry room and one in the large lobby sitting area. The leaks have been found by residents; no waterflow alarms. The sprinkler company who put it in is still doing yearly testing and maintenance. The fire units for these two events found the pressures in the stairwells at 150 psi. The jockey pump turns on at 120 and off at 133. The sprinkler company says the sprinklers in the PVC piping are leaking at the fitting behind the sprinkler and not the sprinkler itself. The connection between the sprinkler and the fitting was either cross threaded or over torqued. Last week I found the gauge on the 6th floor reading 110 psi and the 1st floor at 130 psi. Can pressures of 150 psi plus at extended periods of time cause the leaking? The pipe is rated to 175 psi. The building was built in 1989. And for my own knowledge-the pressure in systems of this type are this high for what reason? We are told the pressures are typical. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is there an FM Global requirement for a minimum safety factor in a hydraulic calculation?
We have a project that is following FM requirements, and the calculation "safety cushion" is coming in at 2 PSI. We have looked through the FM Data Sheets, but cannot find anything to give a minimum criteria. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a non-combustible shell building with 18-inch steel beams under corrugated metal deck.
Some of the beams are spaced in excess of 7'-6" apart, but not exceeding 9'-6" and creating an area exceeding 300 sq. ft. To loosely summarize definitions, per NFPA 13, 2019 edition Section A.3.3.41.1 for Obstructed Construction, Beam and Girder Construction, the steel beams are to be spaced between 3 ft. up to 7½ ft. Panel Construction requires that all cross-sectional areas be filled including the interface at the roof, (which this is not the case on my project), and not exceed the 300 sq. ft. area. My question is this, since this building does not meet either criteria and is not combustible construction, (no wood is being utilized in the structure), there are no concrete tees being utilized and there are no bar joists present, would this then be considered as Unobstructed? My thoughts are no, and that this is still Obstructed Construction, however I can't find a proper definition within the Obstructed Construction definition. I am wanting to know if I can utilize the 1" to 6" below Obstructed Construction allowance however I am held up by the definition of the construction type and am unsure if I need to space within the bays or if I can space below the 18-inch steel beams. Any thoughts or input on this would be greatly appreciated. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does a double wall diesel tank require a reservoir?
Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does NFPA 13 2022 Section 10.2.6.1.1.3 about "Vertical Change in Ceiling Elevation Greater Than 36 in." apply to all types of sprinklers? I have a contractor who argues that the paragraph does not apply to ESFR sprinklers. The design has a change in elevation of 14-feet and the last sprinkler on the high-bay side is 8'-4" feet horizontally from the vertical plane. Thanks for helping settle the disagreement here.
Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have sprinklers at an exterior overhang over 100 feet above the floor (ground) it protects. There will not be anything stored directly beneath the overhang.
There is occupiable space above the overhang. It's noncombustible construction; a mid-rise office tower. Questions have been brought up about heat collection, and the effectiveness of sprinkler spray: if there was a fire on the ground level, will enough heat be collected at the overhang 100-ft up in order to operate an intermediate temperature sprinkler that is 286 degrees F? What will happen if there are high winds (common for this area)? And if the sprinklers do discharge, will the water spray droplets evaporate before reaching a proximity of effectiveness? Will a "cooling effect" even happen? The AHJ will allow the sprinklers to be omitted. I'm not seeing anything specific to very high ceilings in NFPA 13 (2016). My question to you all: Where can I find the science to backup their decision? Do you know of any resources where this scenario has been studied, evaluated, or fire-modeled? (FM or non-FM?) Obtaining a PE review is not a desirable option. (I am aware that FM datasheets address this scenario as requiring sprinklers.) Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I'm working on an existing system in a seven-story building. There is an existing pump and piping which snakes its way through the building.
There is a pressure gauge at the inlet and outlet of the pump, but none afterward until 200' away from the pump room. The pipe branches off with a zone valve assembly with pressure gauge serving that floor area, and then upwards through the remaining floors with no gauge. Zone valve assemblies with gauges are located on the floors above. Now for my question - when performing hydraulic calculations, where would you indicate the "bottom of riser"? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Hi everyone - thanks for answering my previous questions and for checking out today's as well.
I have three projects all connected to the same central fire pump assembly. It's a huge network of pipe running for miles. The client is having a problem with the fluctuating pressure (up and down) on the network for some reason that affects the fire pump's suction pressure. It's in series, and connected to each project. The client refuses to add a break tank and cut the fluctuation. In your experience, is there any alternative solution available? Would a pressure relief valve help? What would happen when the pressure is less than design? Thanks in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe In regards to installing pressure reducing stations for separating areas of the building into different pressure zones, NFPA 14 calls out that the FDC needs to be installed downstream of the pressure reducing valves.
Is a separate FDC required for each pressure zone? If you provide just one FDC, and the fire department supplies the system for an upper floor of a high-rise, you will exceed the maximum working pressure of the lower systems. I'm not sure how that's possible to avoid. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What concerns should I have about hanging from old wood? Like very old wood, almost petrified? I'm doing an NFPA 13R job for an old historic building that has been moved. I don't know how old, but it uses full dimension wood. The 2x's look like they measure 2-inches thick.
I'm wondering what hanging to this old dry wood is going to be like? Do they need to predrill? Are screws better? Any ideas appreciated! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What are the physical or regulatory concerns of leaving an older dry pipe valve as wet for an extended amount of time?
This would be during the non-freezing months. I can think of the alarm trim - water gong changed to electric, clapper gasket integrity, and the inevitable leaks in the overhead system. Curious on other perspectives, thank you! I am working on a project with a new client who develops multi-level Self Storage Facilities.
The typical units are 10'x20' with 8-ft bent metal purlin dividing walls. The walls do not extend to the ceiling deck which is 11'-6" above finished floor. All sorts of household items are being stored, which can include exposed expanded foam mattresses that are greater than 5-ft in height when on their side. The tenants are limited in storage height to 8-ft because of 14 gauge metal wire netting above the units. On previous projects the client has been permitted to classify the hazard as OH2 (possibly because of the definition in NFPA 13, 5.3.2. 2016 edition, which includes contents with high-heat release rates up to 8-ft). The question is whether or not it should be Extra Hazard Group 1 or Extra Hazard Group 2? I am leaning towards EH1. The occupancy is a storage facility so I believe we fall into Chapter 12 for our design requirements. Because we have exposed expanded plastics stored greater than 5-ft we cannot be considered Low-Piled (Chapter 13). Therefore we fall into Chapter 15. Using NFPA13 Table 15.2.2.5(a) and the decision tree, selecting plastic commodities, Group A, Expanded, Exposed, Unstable, I believe the Density would be 0.30 gpm/sqft. This would be EH1. I am using NFPA13, 2016 edition. Can anyone speak to how they would classify the hazard (design area and density) for this type of storage facility? Should it be OH2, EH1 or EH2? Thank you. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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