​We're looking at a fire protection system, Ordinary Hazard Group 2, that requires primary fire protection water from a storage tank.

We are looking at three options, (1) above ground insulated with a heater, (2) underground concrete and (3) underground fiberglass.

I am curious what the community here sees around the industry as being the most common choice here?

The job site already has substantial excavation going on and the job is located in the north east so freezing is a concern. There will be no private hydrant so we don't see the need to carry hose allowance in our tanks sizing.

​Thanks in advance.

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The NFPA 13 sections on cloud ceilings continue concentrate on sprinklers above the cloud ceilings, not the sprinklers in the clouds themselves.

If the area above the cloud is sprinklered throughout, yet there are multiple clouds greater than 4-ft wide in the shortest direction (all at the same elevation plane), creating obstructions to the sprinklers above, does each cloud obstruction need to be treated independently for sprinkler coverage beneath, or can the designer “skip” clouds or portions of the clouds and gaps, as long as the overall pendent sprinkler spacing does not exceed the maximum spacing for the hazard?

I would think the opening width between the clouds would play a role in this as well, the heat's ability to skip the gap. And whether or not the sprinklers above are able to develop their spray pattern.

I often see designs with sprinklers in clouds spaced out 15' x 15' leaving some clouds without sprinklers. As far as I can tell, even the 2022 edition and handbooks are silent on this.

Thanks in advance.

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We have a skylight scenario that's slightly different than a prior discussion here.

NFPA 13 Section 8.5.7.1.1 states:
"when a sprinkler is installed directly beneath a skylight not exceeding 32 sq.ft., the distance to the ceiling shall be measured to the plane of the ceiling as if the skylight was not present".

Two things I'm not understanding here:

1) "..sprinkler installed directly beneath..": does this mean a sprinkler in the opening, somewhere in the depth of the skylight, from the finished ceiling up to the clear glass?

2) "..as if the skylight was not present." : the way I'm interpreting this is the distance from where the sprinkler is installed (the deflector) at the lower ceiling level - or we could say at the ceiling level where the skylight opening is - can be measure as if the skylight isn't there, meaning the deflector should be placed a min. 1" down from the opening, even if from the opening to the skylight glass is say 5 feet?

If that is the case where a sprinkler is installed in this manner (so as to ignore the depth of the skylight), then here's one last proposal/query: a bulkhead is installed at a lower elevation than this ceiling level. So now, are we able to implement ceiling pocket requirements?

The total volume of ceiling pockets is less than 1000 cu.ft. in the compartment, and with the other requirements fulfilled from 8.6.7.2, we'd be able to get away with sprinklers only in the the lower bulkhead ceiling.

My issue with this though is the presence of the skylights. Hoping someone can help me out here. Thank you.

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Does a diesel-powered fire pump require a full flow relief valve to prevent over pressurization due to a RPM governor failure?

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In Class I standpipes, I commonly see a pair of hose valves installed at the top landing (or intermediate landing) - One immediately below the other.

Is this an incorrect derivative of the requirement to calculate the two most remote outlets (at 500 gpm), or something that was required in a previous edition of NFPA #14, or is this merely a regional practice that is a result of the shared DNA of my regional contractors?

I thought I had seen an informal interpretation regarding this, but I cannot find it again. NFPA Figures do not appear to support this double-valve arrangement.

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I'm quite familiar with conducting hydrant flow tests, NFPA 291, and have read articles such at the Sprinkler Age article from Feb. 2018. And I know the residual hydrant should be between the hydrant(s) to be flowed and the large source mains for the area.

But in terms of a specific project site (especially if the underground is well-gridded), would you chose the hydrant closest to your project to be the static/residual hydrant, or would you select the flowing hydrant to be closest to your project (and adjusting the static/residual for any elevation difference)?

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Under NFPA 20, Section 4.20.7.1: 

The circulating relief valve shall actuate below the opening set point of the pressure relief valve to ensure cooling of the pump during churn operation.

NFPA 20 Handbook:
​
The pressure setting of the circulation relief valve should be well below the pressure relief valve setting but above the maximum suction pressure.

Based on this, how do I properly specify the circulation relief valve setting that is installed on the pressure relief valve discharge line if the pressure relief valve set point is 175 psi?

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For seismic bracing, can one lateral and one longitudinal brace, attached within 2-foot of a drop to the floor below, be considered a 4-way brace?

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This isn't really a question, but I wanted to see if anyone would be willing to share drawings they have done in the past with me?

I am looking to improve the look of our drawings, provide the AHJ with clear and concise information, and provide an all-around great end product. Thank you in advance!

If company information, logos, location, address, etc need to be removed or blocked in order to share the drawings, I understand.

Editor's note: We love this idea. If you're looking to share a sample (or set), email it to us at [email protected], and we'll update this post with images and links for discussion as they come in. Your images/drawings can be anonymous or credited, whichever you'd prefer. This could be a neat opportunity to discuss likes/improvement ideas.

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We have been asked to supply FDC signage for an existing building with combined sprinkler/standpipe system.

The AHJ has requested that both minimum and maximum operating pressure be included on the sign.

Can we use existing hydraulic data information or should it be recalculated including friction loss from the fire hose to pumper truck?

Also, what would constitute the maximum pressure in a combined sprinkler / Class III system?

Would it be max 175 psi at all 2-1/2” hose connections if there are pressure regulations devices on the 1-1/2” hose valves?

Thanks in advance in helping us sort this out.

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During a recent life safety walk through of a popular boat show, I observed the installation of a temporary Class I wet standpipe system to supply various hose valves along the docks.

I noticed the 4-inch Silver-Line Schedule 40 PVC pipe was being supported randomly. I recorded distances ranging from 9 to 15 feet. I consulted with NFPA 14 then 13.

NFPA 13, Table 17.4.2.1 shows "NA" for 4 inch CPVC pipe. In viewing the cut sheets for the listed pipe, the support spacing is 7.7 feet at 73 degrees F.

My question is, is my methodology correct on how I went about getting the correct spacing in order to advise the the contractor?

Please advise. Thank you.

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We have a project that is Type III-A, wood frame construction, with an NFPA 13 sprinkler system.

The client is weighing options of filling floor truss cavities with non-combustible insulation versus adding sprinkler coverage within these floor-ceiling cavities.

Does anyone have recent experience to know the relative cost impact of adding sprinklers within these floor cavities?

Thanks in advance.

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We have a project that has a dedicated fire water supply storage tank. Is an FDC required on this setup?

Thanks in advance.

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We have a warehouse with all steel parts and materials. There are no pallets. 

If these parts and materials are stored on 25-foot high racks, does the design criteria of Chapter 16 in NFPA 13 (2016 Edition) apply for a commodity like this?

​Am I missing something critical here?

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We have a 300 sq ft control area (1 hour rated) for storage of Class IB flammable liquid. The 2018 IBC Table 307.1 permits 120 gallons (no sprinklers required), but this amount can be doubled if the building is equipped with an NFPA 13 automatic sprinkler system.

Our client would like to store about 165 gallons in the room (3 drums). The building is fully sprinklered.

What is the required sprinkler design density for this room?

We considered Ordinary Hazard Group 2 (same as lab area it supports) or Extra Hazard Group 2 (only occupancy in NFPA 13 that mentions flammable liquids).

If EH2, then the minimum water demand becomes quite large: 0.4 x 2500 + 500 gpm hose = 1500 gpm (Under the 2016 NFPA 13 - Section 23.4.4.2.5).

Could you help point us in the right direction? Thanks to all in advance for helping us hunt this down. 

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I have an S-1 occupancy. It is a privately owned storage unit (no public access) used for the storage of exotic cars, maybe 3 vehicles in total. The space is about 1,400 square feet, and is fire sprinkler protected. There is a wood-framed mezzanine at the back of the unit as is about 300 square feet.

The question that has come up is if the underside of the open wood stairs to the mezzanine needs to be protected with fire-retardant gypsum board?

There is no sprinkler coverage under the stairs. The mezzanine may be built out by the owner to have a few chairs, a couch, a television, etc.

Digging into the code talks a lot about accessibility but not so much about the fire resistance requirements for the stairs. I have the found following in the 2015 IBC (code we are under):

1104.4 Multistory buildings and facilities. At least one accessible route shall connect each accessible story and mezzanine in multilevel buildings and facilities.

Exceptions
1. An accessible route is NOT required to stories and mezzanines that have an aggregate area of not more than 3,000 square feet (278.7 m2) and are located above and below accessible levels. This exception shall not apply to:

...and...

4. Where a two-story building or facility has one story or mezzanine with an occupant load of five or fewer persons that does not contain public use space, that story or mezzanine shall not be required to be connected by an accessible route to the story above or below.

So...the accessibility issue is covered but nothing about the rating of the stairs that I can find. Any help would be appreciated. Maybe I am not looking in the correct code section.

Thank you!

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Is there a calculation program to estimate the water delivery time for a dry system, that works on AutoCAD?

Looking for options in this area. Thanks.

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First - I really appreciate this forum. The discussions here are great - sometimes quick & easy and sometimes with a lot of depth. Also appreciate the variety of perspectives we each see the same industry. So thank you. Also - my question today isn't concerned about the people on this forum. It's clear that you care and are knowledgeable, so wanted to lay that out there.

At what point am I obligated to report negligence?

I've seen some projects out for bid that are five-story apartments with NFPA 13D issued on the drawings. I've seen hazard criteria that is (black and white) below code minimums out of NFPA 13. Underground pipe stretching 40 feet before stubbing up into a building. Not small things-big things. 

Not just missing the mark - but clearly unprofessional and probably considered to be gross negligence by some lawyers (I am not one). They're signed/sealed and put out to the world for bid.

I don't see this all the time, but it does come up. I'm not an AHJ but my guess is they'd have much worse horror stories. These things can all be corrected - RFIs or plan review or with inspections. But at what point is something so far off that it's not a mistake and is actually something that should be reported?

Are AHJs handling these things behind the scenes and I just don't know about it?

I don't want to be the bad guy and I don't feel like it's my personal fight to stand in front of each state board and state a case why someone else missed something. But at what point do I become part of the problem if I don't report it?

Do states have anonymous tips for the license boards?

Has anyone gone this route with any real effect?

Again I want to be part of the solution, not the problem, but I also don't quite feel like this is my life's crusade either. I am curious how others would go about addressing this issue and what advice you might offer to a younger person in the industry. Appreciate the conversation, thanks.

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Given the HFC (hydrofluorocarbon) production phase-out, what are you currently recommending to your clients and customers regarding the installation of new FM-200 systems at this time?

Just curious to get a status check on how you approach this challenge. Thanks in advance.

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When is C900 PVC allowed below buildings before the transition to metallic pipe for spigot stub up?

I often see municipal rules to keep non-metallic pipe no closer than five feet from the building foundation. 

Where does this requirement come from?

I have no problem with this practice but would like some code justification to discuss this with contractors.

Thanks in advance.

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I have a project that consists of a concrete deck and a solid decorative wooden ceiling suspended about 1-foot below the deck. I'm trying to determine if this condition would create a combustible concealed space per Section 8.15 of NFPA 13 (2013 edition). The section touches on the construction of structural elements, but not really the construction of the ceiling itself.

Unfortunately, I have not been able to verify the supporting structure of the ceiling as is difficult to access above due to its age and level of ornate detail. I also question the feasibility of being able to protect above this ceiling for those reasons.

If the space is considered a combustible concealed space and the preference is to omit sprinklers from the space, is the course of action at that point to increase the hydraulically remote area to 3,000 sf and omit protection?

​Thanks everyone!

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I wanted to pose the question on hazardous material storage lockers. We wish to protect the locker in accordance with Chapter 14 of NFPA 30 and have rated it for 4-hours to eliminate the need for fire separation distance to the immediately-adjacent main building as allowed.

The locker will not be structurally attached and will only have flashing connecting the two to keep out the elements, garbage, and animals. The locker will only have people in as necessary to get the liquids out.

The main building has a door on the "exterior wall" that opens and "reveals" the 3-hour rated hazardous material locker door, which you have to open to get inside the locker.

NFPA 30 2015 handbook Section 14.4.3 denotes that lockers over 1500 sqft should be protected permanent building such as attached buildings or warehouses. Our locker is under the 1500 sqft requirements so therefore I would say we are not a building but a "locker".

Therefore, the exterior wall openings allowances of IBC (2015) Table 705.8 would be to the lot line (over 10ft) and not the locker itself (0ft), allowing our client to access the locker from the inside of the main building and not having to go outside to access it from the exterior.

I was wondering if anyone has had a similar experience or if we should just call it part of the main building and protect it as such and lose the allowances of Chapter 14.

Thanks in advance!

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Shout out to the top contributors for February 2022 - thanks for making the forum something special!

When doing an annual test today for large fire pumps with a combined test header, I was told that most inspectors throttle and send water to the pitot gauges by using the butterfly valve inside the pump room and keeping the control valves wide open outside on the test header.

I disagreed with this approach, as my mentor in the industry taught me to first charge the test header and then get your pressures by opening each outside control valve individually to get your pressures. He said this is so that you don't burn up the rubber on the inside test header (normally-closed) butterfly valve. He said it happened to him in the past and then the building owner is left with a leaking test header control valve and the danger and costliness of a test header full of water.

Is there a correct way (by code) to get your pitot reading off the hose monsters outside (what I mainly using) or is charging water one way or the other simply a matter of preference?

I hope this makes sense.

I understand some test header control valves are OS&Y but most all the outside components I come across are the test hose connections that open and close via the gate valve.

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