Can full height walls within a room create an obstructed construction situation in an otherwise unobstructed construction building?
As an example, you have a room with full height walls and a single exposed beam (in noncombustible construction) with the distance from the centerline of the beam to both parallel walls less than 7'-6". If allowed to define this as obstructed construction, a single sprinkler 1" to 6" below the bottom of the beam may be sufficient. If not, it may require a sprinkler on both sides of the beam. In a multiple-office type of occupancy this could save a lot of sprinklers. This example is assuming following all the rules for obstructed construction and the depth of the beam being such that you can't use the obstruction to sprinkler discharge rules to avoid the obstruction. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
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Topic: Water Delivery Time in Single Interlock Preaction Systems Question:
I'm currently designing a single-interlock preaction system and I'm seeking clarification about the water delivery time requirements under NFPA 13 (2013). Section 7.3.2.2 mentions that the system size cannot exceed 1,000 automatic sprinklers but doesn't specify the water delivery time for single interlock systems. On the other hand, Section 7.3.2.3 clearly states that double interlock preaction systems must deliver water within no more than 60 seconds. Does this mean that single interlock systems are not required to adhere to a specific timeframe for water delivery? In my view, it makes sense to not include a delivery time for single interlock systems, since water should already be at the sprinkler prior to activation. I'm interested in others' views or experiences in this area. Thanks in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a building that has both a free standing fire department connection (FDC) and a post-indicator valve (PIV) out at the drive entrance to the single-story building as requested by the Fire Marshal.
Construction has now started up for the site and the Fire Marshal is saying there is a code requirement for the PIV and FDC to be 50-ft apart and wants them moved. He is unsure of the exact distance, but he insists this is a code requirement and that it's not a local requirement. For reference, we are under the 2015 IBC/IFC and 2013 NFPA code editions. Is there any requirement for the PIV and FDC to be 50-ft apart? I cannot find any requirement like this in the IBC, IFC, or NFPA 13 or 24. There are sections in both NFPA 13 and 24 that vaguely say PIVs shall be protected against mechanical damage, but they give no minimum distance from objects. IFC/IBC both list minimum 36-in clearance around the FDC. I think the Fire Marshal might be confusing the 40ft requirement from buildings for the PIV, or, this is a local preference, but they do insist otherwise. I know at the end of the day the Fire Marshal gets whatever they want for the PIV and FDC placement, but I really want to make sure that there is not some hidden requirement I cannot find. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a project in the Miami area where there are some exterior glass panels that need to be 1-hour fire rated.
I specified the glass to be fire rated type, but it prices are coming back too high. The contractor is looking into an alternative of providing fire sprinkler protection on the inside face of the glass. Is this a feasible idea? The wall that the glass is part of requires the rating due to its being within 10' of some adjacent exterior glass. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a fire sprinkler tree system that has a 6" centerline down from a metal deck (mains and lines).
Since an air release valve is required at the end of the system, what are our options for installation? All the options I can find are too tall to fit with our piping so close to the deck. We are not able to lower the piping due to other trades. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a steel aircraft storage hanger Group 1. It's approximately 50-ft high with exposed steel columns requiring a fire rating per NFPA 409-2022 Edition.
The steel will not be fireproofed but will be protected with sprinklers in accordance with NFPA 409 5.6.3.4. Can pendent sprinklers, installed sideways, be used to satisfy NFPA 409 for column protection? In the past we have protected the columns with sidewall sprinklers spaced according to 409 and on alternating sides of the column. Then the sidewalls were changed to pendent sprinklers installed horizontally to provide better spray distribution on the columns as the sidewall spray tended to (in theory at least) bounce the spray back in stead of vertically. This approach has been accepted by EOR and AHJs alike. NFPA 409 states that "wetting of the lower sprinkler should be considered" although multiple level sprinklers were never used. I'm not sure how this plays in. I recall reading that pendents installed horizontally could be used for column protection due to better spray distribution, however, I cannot find that in code. The client is not open to fireproofing or intumescent paint; column sprinkler protection is in the bit and is going to be used. All is appreciated! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Does anyone know of any literature summarizing standpipe design changes history for the last 130 years or so?
Something to the effect of:
With more enforcement of 5-year standpipe flow testing in our area we find ourselves spending a lot of time trying to locate older versions of NFPA and NBFU to see the design basis at the time of construction to determine testing procedure. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can an assisted living facility that installed a an NFPA 13 compliant system which was only required to be a 13R now remove the dry attic part of the system?
They have had corrosion issues and leaks they are wanting to avoid. The only reason they installed the 13 system is initially they envisioned possible adding a skilled care section which is now not happening. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe In regards to a trapeze pipe support, isn't there an option to size the rod that connects structure to the trapeze pipe separately from the rod from the trapeze pipe to sprinkler pipe?
Couldn't that be two separate calculations considering there are two rods for the trapeze and only one to the sprinkler main? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Would you require a pressure gauge on the bottom side of the backflow device? NFPA 13 says pressure gauges shall be installed above and below each “alarm” check valve or “system riser” check valve where such devices are present. Is the backflow preventer considered an alarm check or riser check valve? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is CPVC allowed to be run exposed through a small storage room?
Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a showroom with an open mezzanine that takes up around 30% of the floor area. The bottom and the top of the mezzanine are office areas. The showroom has a ceiling height of 23-ft while the mezzanine has a ceiling height of 11-ft.
We designed the the showroom as Ordinary Hazard using standard response, extended coverage sprinklers (18' x 18') on the ceiling with the top part of the mezzanine also being protected with standard response, extended coverage. There are no walls on the top side of mezzanine. On the flip side, we designed the bottom part of the mezzanine using Quick Response, Light Hazard (15' x 15' ) spacing since it's an office (Light Hazard occupancy). However, since this is an open mezzanine with no walls separating between the two spaces, this means that both these areas would be considered one compartment. Under NFPA 13, sprinklers in the same compartment should be the same response type and hazard levels. However, would the elevation difference and the mezzanine floor separating the two make it okay to have two different type of hazard level and response type? If not, what about adding draft curtains? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a tree, wet system, we are using Schedule 7 for the mains and branch lines.
We are trying to design the seismic bracing, and the main is only strong enough for one side of branch lines, not the opposite side too. Should we use stronger pipe, or install more laterals? Is there a way to brace the branch lines to take the weight off the mains? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe What is the difference between feed main and cross-main in a sprinkler system?
As NFPA 13 mentions, feed main supplies the cross mains but in tree sometimes main pipe continues and supply the branches. What's the difference? Are we talking about each individual piece of pipe? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a dining room in a clubhouse that has multiple ceiling pockets at different sizes that are 1-5" in depth.
The total cubic footage of these pockets is 1,165 cubic feet. Could I protect one of the pockets in this space to bring my total unprotected pockets under 1,000 cubic feet, and leave the rest of these pockets unprotected? The entire floor space in this area will be protected. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe I have a K14 ESFR system in a tall building; 45-ft peak and 35-ft eaves, that was hit by the changes in NFPA 13 and there is now a recommendation to upgrade protection to K25 ESFR sprinklers due to the roof height.
The current design is a very strong 12 K14 @ 90 psi and the storage is low at 16-ft of palletized Class III and IV goods. Based on the current storage arrangement, 2022 NFPA 13 allows for either K25 ESFR system or a CDMA design of .64/2,000 using ordinary temperature sprinklers. Is is permissible to recalculate ESFR systems with a CDMA design? If so, is there any specific mention or directive in code? I am not a designer but back of napkin math indicates I have a 1.33 gpm/sqft. density over the first 1,200 sqft based on the ESFR design and probably a .80/2,000. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Can all main drains can be joined in one pipe?
If they can, does this pipe need to be capable of handling all flow at the same time? Are there any downsides to ganging them together? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Where would I go to find CMDA protection of Rack Storage less than 12-ft?
In this particular case, I'm looking at Class III commodities on wire racks in a 2,000 sqft room with 8-ft ceilings. This is paper file storage. In the past, I have been able to use the miscellaneous storage requirements, but not this time. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a car park area which is part of a bigger development that we are sub-dividing into different pressure zones due to it being a very tall building. The three levels of car park in total are less than 65-ft (20 m) high, but they are very long and wide. My question is about sprinkler control valve areas.
I know for ordinary hazard the restriction per floor from one riser is 52,000 sqft (4830 sqm) with no restriction as you go up. Does that mean for a wide, low-level building, say on 1 level, do we need a system riser for each 52,000 sqft? This seems pretty onerous to me, as FM Global do not even insist on this. Here in England, the restriction is 12,000 sqm x 10 floors per valve. I'm being asked by the authorities to allow the valves, but is that restriction of 52,000 sqft (4830 sqm) per valve set on a single floor set in stone? Can we do something based on hydraulic calculation that is more user friendly? Thanks in advance. Does NFPA 13 address the ability to size sprinkler pipe simply by being "sized by similarity"?
For instance, I have a small room that has (4) 1/2" pendent sprinklers to be located in it. I cannot determine any pipe routing from above due to an old ceiling but can verify the lines are 1-1/2" schedule 40. I've heard of this method being used but do not find it in NFPA 13 so I'm hesitant to use this method. Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe Is there a room volume cut off that you use for clean agent space to make sure that your system will pass the room integrity fan test?
As an extreme example, a 50,000 sf space would probably be better for something like a double interlock preaction system since it would be difficult to make sure that the space is of tight enough construction to hold the clean agent (there will inherently be some leaks in construction despite doing all the recommended practices of gasketing, door threshold blocking, etc). Thanks in advance! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe For a project that has seismic expansions and the fire sprinkler piping is predominately CPVC, are seismic loops or assemblies still required?
If so, is there are preferred installation method? Would we need to transition to steel, then back to CPVC, in order to install a Metraflex or similar product? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have an ESFR project with Obstructed Construction and want to be sure we're locating the height of the sprinkler 100% correct. This is an FM-Global project.
We are using K14 ESFR uprights. The bays are 25-ft x 25-ft boxed with W27 beams and contain small bays with W18 beams that are 6'-3" in-between. As far as I can tell, the sprinkler height is compliant as long as the center of the operating element does not exceed 6-inches below the W18 beams, to a maximum of 22-inches below the deck. So 4-inches maximum below the W18 beams is the target. We're using Table 8 in FM Data Sheet 8-9 for the design criteria. Is this approach correct? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe NFPA 13, 2022 Edition, Sections 28.2.4.2.4 says to that a design area can be only the sprinklers within the available design area whenever the available floor area is less than the density/area size.
The next section, Section 28.2.4.2.5, says that when the total flow is less than the density x minimum design area, an additional flow (phantom flow) shall be added at the common point of connection. When do you apply one versus the other? If I am interpreting this correctly, you only apply the 28.2.4.2.5 when you have the available floor area, but not the minimum flow? Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe We have a passenger elevator that is a traction, machine room-less (MRL).
Under NFPA 13, 2013 Edition, Section 8.15.5.2, a 'sprinkler shall not be required for enclosed, non-combustible elevator shafts that do not contain combustible hydraulic fluids.' NFPA 72, 2013 Edition, Section 21.3.6 states that 'smoke detectors shall not be installed in unsprinklered hoistways unless they are installed to activate the elevator hoistway smoke relief equipment.' I believe these would apply to this elevator. Does the elevator only require lobby smoke detectors, including first floor for recall and second floor for alternate recall? Is a smoke detector actually required within the shaft? This is my first MRL elevator and I want to make sure we cover everything that's required. I would appreciate you views on this, thank you! Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe |
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