Are ESFR heads provided below obstructions required to be calculated in addition to, in lieu of, or ignored when compared against the 12 (three rows of four sprinklers) included in the hydraulic calculations?

I haven't designed an ESFR system in ten years and it looks like the new verbiage seems to suggest that sprinklers below obstructions are not included in the calculations. Thanks in advance!

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I live in a 28-unit condominium with a dry system that we agreed to have the valve & compressor replaced in September 2020. The previous system's air compressor ran 2 times every 24 hrs for 16 mins. The new air compressor ran every 4 minutes for 8 seconds & was very loud in an enclosed room. This new air compressor quit after 90 days & breaking at 2 separate times on the copper lines.

How can we cut down the noise and make repairs?

As of today (March 2021), we have had a Cobalt compressor running in place of the general compressor that quit. The Cobalt runs every 70 minutes for 2.5 minutes. We are constantly told by contractor we have a leak somewhere that needs to be addressed, that we don’t doubt. We have cut the air off for a leak check, 2.5 hrs 2 lbs down.

I know this lengthy but I need some advice how to cut down noise and repairs. Thanks for any help.

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The International Fire Code (IFC) Section 6004 for highly toxic and toxic gases states the following for exhausted enclosures:

6004.1.3(1) The average ventilation velocity at the face of the enclosure shall not be less than 200 feet per minute with not less than 150 feet per minute.

However, in the same section for gas cabinets (Section 6004.1.2(1)), the words "at any point of the access port or window" are added after "150 feet per minute."

Doe anyone know if this was an oversight by the authors of this section? Did they miss a few words in the requirement for exhausted enclosures?

I don't understand why the 150 feet per minute would be for gas cabinets but not exhausted enclosures (albeit without referencing where the 150 feet per minute measurement is to be taken). This issue is coming up at my work as we have several exhausted enclosures and gas cabinets and some of the exhausted enclosures have ports/windows which are sealed shut. Thanks in advance!

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I have a skylight that is 4-ft (length) x 6-ft (width) x 5-ft (depth). The room has a drywall ceiling and the depth of the pocket is about 4-ft of dry wall between the ceiling with an additional 1'-0" of glass (for the skylight) that domes above the roof at the top of the pocket.

Can I omit a sprinkler in the skylight per NFPA 13 2016 Section 8.5.7, or do I need a sprinkler in the skylight under Section 8.6.7 due to the depth of the unprotected ceiling pocket exceeding 36-inches?

NFPA 13, 2016 Section 8.5.7 (Skylights) permits sprinklers to be omitted from skylights not exceeding 32ft² that are separated by at least 10ft horizontally from any other unprotected skylight or unprotected ceiling pocket.

NFPA 13, 2016 Section 8.6.7 (Ceiling Pockets) says sprinklers shall not be required in ceiling pockets where all of the following are met: (1) The total volume of unprotected ceiling pocket does not exceed 1000ft³.(2) The depth of the unprotected ceiling pocket does not exceed 36 in. (3) The entire floor under the unprotected ceiling pocket is protected by sprinklers at the lower ceiling elevation. (4) the total size of all unprotected ceiling pockets in the same compartment with in 10ft of each other does not exceed 1000ft³. (5) The unprotected ceiling pocket has noncombustible or limited-combustible finishes. (6) Quick-response sprinklers are utilized throughout the compartment.

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We have a paper plant that has storage of rolled tissue paper stored up to 16-feet. While researching the protection requirements in NFPA 13 I discovered this commodity class at these heights can be protected by CMDA designs, but not CMSA or ESFR. I have been unable to find why CMSA and ESFR isn't allowed in NFPA 13 (handbook and other resources).

Do you have any idea why CMSA and ESFR wouldn't be permitted for this hazard?

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Editor's Note from Joe: Sorry for the swing and the miss yesterday everyone! Didn't get the post up, so we're putting up two questions today. Hope you have a great rest of your week!

We're under the International Fire Code, Section 903.2.11.5. This section allows fire sprinklers to be installed in commercial hood/duct systems.

Is this intended to be in the ductwork only, or also protecting the cooking equipment?

I've never seen this before, but it seems to go against everything we're taught about cooking and grease fires (don't put water on them)! Thanks in advance.

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We have a project where the contractor tied in a new 4-inch standpipe into the existing 6-inch sprinkler main riser. Now it becomes a combination standpipe/fire sprinkler riser. 

My question is - does the contractor still need to install riser isolation valves on every floor? 

Per NFPA 13 8.17.5.2.2* the following restrictions shall apply:
(3) Each combined sprinkler and standpipe riser shall be equipped with a riser control valve to permit isolating a riser without interrupting the supply to other risers from the same source of supply. (For fire department connections serving standpipe and sprinkler systems, refer to Section 6.8). 

As of now the sprinkler main riser is not a part of their scope. Thanks in advance.

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Can you help explain two entries in NFPA 13-2019 Table A.20.4(b) for "Empty Containers" on page 418?

Rigid plastic (not including PET) up to 32-oz. (1L) is non-expanded.
Rigid plastic (not including PET) greater than 32-oz. (1L) is expanded.

What are they referring to? Is this a one-gallon PE bucket? A 64-oz. detergent bottle? Milk crates?

I guess my question is - what is a rigid plastic container?

There's a huge difference if it needs to be treated as an Exposed Expanded Group A plastic versus Non-Expanded.

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We have a Type II-B construction mostly light-hazard building with drop ceilings throughout. The plenum is not sprinkler protected. Walls go to either the ceiling or roof deck, depending upon the use of the space (ie: conference rooms have full-height walls for acoustics).

There is a closet which does not have a ceiling, and its' walls do not go to deck.

Does this opening invalidate the elimination of sprinklers in the plenum from NFPA 13 (2013/2016) Section 8.15.1.2.2 for non-combustible and limited-combustible spaces?

Would posting signage saying no combustible storage is permitted in lieu of extending the walls work instead of installing a ceiling?

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Is there a recommended maximum distance between the Fire Department Connection (FDC) and check valve?

NFPA 13 does not include a required maximum distance between the check valve and the FDC. I understand the intent is to reduce the length of non-pressurized pipe. My project includes a warehouse with a free-standing FDC located about 125-feet from the building.

Is it best to locate the check valve indoors, where it can be easily inspected and maintained, or, located underground, closer to the FDC where it would be buried?

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Our fire water demand capacity is 60,000 gallons, but our current water tank storage capacity is 30,000 gallons. We don't have any space near our current fire water storage tank. 

Is it possible to make another (second) tank with a capacity of 30,000 gallons and connect it to the old tank through pipe?

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Is a pumper truck from the fire department required to do standpipe flow testing?

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A special thank you to the top contributors for this past month!

Can the ceiling pocked omission rules outlined in NFPA 13 for standard spray pendents and uprights be applied to standard spray sidewalls?

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Has anyone come across a dual riser (dual-feed) sprinkler system in an office tower, with only a single inspector's test?

What is the proper method of testing each flow switch?

In most cases, only the flow switch nearest the inspector's test will operate in a timely manner. Some inspectors will isolate and test, others believe the system should be tested under normal conditions with both control valves open.

Is the deficiency the lack of a second test connection, or that the flow switch doesn't operate within 90 seconds (or even 5 minutes)? Alternatively, is there no deficiency at all?

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Is there a method to use a main drain test to calculate the hydraulic curve at the riser itself?

I haven't done it myself, but using a static pressure at the riser, with a residual pressure at the riser, and then to gather the flow a pitot reading on the main drain discharge to measure how much flow?

If the flow discharge outside was greater than the demand of the system, conceivably a hydraulic calculation could be made with the riser as the source point, and with more accuracy than a hydrant flow test somewhere near the site.

Obviously if a backflow test header or hose valve were supplied, a higher flow could be obtained with a better curve.

I heard this mentioned recently so it's just theory to me, but for small remodels having a setup like this could be far simpler (and potentially more accurate) to know the available water supply at the system.

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In our area, wet standpipe/sprinkler pipe running through unheated parking garages always gets heat tracing and insulation. 

On this current project, the general contractor wants us to run a 4-inch main as high as possible to a 7.5-inch thick post-tensioned concrete deck that has a heated space above it and a 24 deg F 1% design temperature below in the garage. They're looping 14-inches of batt fiberglass with a plastic barrier below it creating an envelope around the pipe.

The general contractor is questioning whether the heat tracing is needed. We've got plenty of experience 'tenting' sprinkler pipe in attics but never under concrete. I've suggested they hire a mechanical engineer to do the calculations.

Does anyone have experience with this situation?

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Is anyone having problems with steel pipe corrosion after using the older glycerin?

Three year old condominium complex was an NFPA 13R job. About 75% of the pipe is CPVC with exposed basements installed in steel. We hydo-tested four of the buildings in the winter with the glycerin before the buildings had heat so the builder can insulate and sheetrock. We drained out what we could but did not pull any heads in the basement. We didn't think leaving some trapped glycerin in the steel basement piping would be anything to be concerned about.

The basements have developed pin hole leaks and the odor when draining is putrid! I saw the new UL-listed (Freezemaster) antifreeze states, "includes a corrosion inhibitor package".

Any help/advice is greatly appreciated in stopping this attack on the pipe.

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I get asked by building owners somewhat frequently - what is the required clearance from a sprinkler?

I understand most typical ordinary storage/miscellaneous storage/office/standard spray sprinklers the clearance is 18-inches.

I also understand ESFR requires 36-inch minimum. I'm trying to understand the big picture and not misspeak. 

What about other sprinklers, like CMDA, CMSA? Is there a rule of thumb across the board?

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Does anyone have recommendations for who would perform inspection, testing & maintenance  (ITM) on deflagration vents under NFPA 68?

My company is having trouble finding a reputable organization that will take it on. The supplier of the chemical explosion prevention system with has turned down the work. There is a push from some to let our own maintenance handle it, per the checklist in the annex, but I feel that a group with this expertise would be a better fit. Thanks in advance.

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Having trouble getting a good feel for fire sprinkler design criteria for compact, mobile storage shelves. These contain Class I-IV commodities. As I understand it, NFPA 13 only covers light hazard for compact shelving.

The metal shelves have a height of 8-feet, the ceiling height is 26-feet. The room is 3,000 sqft, and the shelves have a footprint within that space of 21 x 30 feet. Any help is appreciated. 

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We have a four-story project that uses NFPA 13R - 2016 Edition. There are balconies with wood structure that are getting sprinkler protection. The building is in a cold climate.

I'm trying to figure out how to correctly incorporate these balcony sprinklers in the hydraulic calculations while still being efficient in the sprinkler design (there's no fire pump on this and poor city supply).

As I understand it in NFPA 13R, my options are:

(1) NFPA 13R for Dwelling Unit Calculation: use dry-sidewall residential sprinklers (Reliable and Tyco have some) for the balcony. This would then be a 0.05 gpm/sqft calculation over a compartment, up to four sprinklers. 

(2) NFPA 13R for Outside of Dwelling Unit: use dry-sidewall quick response sprinkler for balcony. This would be a 0.10 gpm/sqft calculation for four adjacent sprinklers. The inside sprinklers could still be 0.05 gpm/sqft (per 13R), but the balcony sprinklers need to be 0.10 gpm/sqft (per 13R 7.2.2, 7.2.3).

(3) If the balcony is under 500 sqft and meets a string of conditions, then dry-sidewall quick response sprinklers for the balcony can be for the compartment, up to four sprinklers (per 13R 7.2.3.1). We don't meet this here, because there are large glass slider doors over 50 sqft.

Are there other options here, or is my approach for the first two options appropriate? I could very well be overthinking this. Thanks in advance.

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We are designing a clean agent system for electrical rooms located within a high-rise building. We are proposing having dedicated clean agent releasing control panels for the electrical rooms, and a separate building Fire Alarm Control Panel.

Is it mandatory to connect fire/smoke dampers (and other shutdown devices) in the electrical room with the clean agent releasing panel, or can these be connected to the building fire alarm system?

Thanks in advance.

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