Submitted: I recently came across a project that was out for bid and in the engineer's specifications required all bidding submitters to provide complete plans and hydraulic calculations to be submitted with their bid. I almost laughed out loud.

This wasn't a basic project (senior care roughly 130,000 sqft), but also not a project with some sort of critical design needs either. I would be curious to have a poll, specifically for contractors and their design teams, that asks about how much effort (square footage / layout sprinklers / layout sprinklers and pipe / calc & size pipe / complete material lists) they typically put into an estimate when they only get "performance-specification" or "design-build" specifications.

I don't know if some engineers know (or care) how much effort goes into bidding, but I'd be interested to see what the industry as a whole does. Of course when bidding, all that time is at-risk of being completely wasted without winning the bid.

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In your opinion, what's the best way to address sprinkler design when there are open breezeways separating units in the same building?

Do you somehow provide a heated chase under a deck? Convert from CPVC to steel and heat-trace a run? Go back underground and potentially "under" the building? Use separate risers for each grouping, bumping up the price significantly?

Residential multi-unit apartment complexes are frequently built with open breezeways in-between blocks of units. These usually have paved concrete at the bottom, only wood joists and decking for stairways and walking areas, and a covered roof at the top. 

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NFPA 13 has the hydraulic remote area reduction for use of Quick-Response sprinklers for wet, light/ordinary hazard, low(er) ceilings without pockets.

Does FM Global recognize anything similar for the use of quick-response sprinklers, or is their HC-1, HC-2, and HC-3 categorization the minimum remote area size regardless of sprinkler RTI? 

​I've checked FM Global Data Sheet 2-0 and 3-26, but have yet to find anything similar in nature.

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Per NFPA 415 (Section 4.5.1.3) “Passenger-handling areas shall be classified as Ordinary Hazard Group 1 Occupancy, as defined in NFPA 13, for the purpose of sprinkler system design.”   

Is there a guideline to what areas in an airport are “Passenger-handling areas”? There isn't a formal definition in NFPA 415.

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I have a project that is Seismic Design Category D. I'm researching and I thought there were requirements that stemmed from the Northridge Earthquake in 1994 related to the limiting the height/length of the sprinkler service entry.

Is there a 5-foot limit from the underground to the riser for seismic projects?

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Could Fiberglass Reinforced Polymer materials be considered non-combustible? For this project it's intended to be used as an interior building material.

NFPA 130 & NFPA 101 definition of non-combustible material:

4.7  Non-combustible material
A material that complies with any of the following shall be considered a noncombustible material [101:4.6.13.1].

1. A material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors, when subjected to fire or heat. [101:4.6.13.1(1)]
2. A material that is reported as passing ASTM E136. [101:4.6.13.1)2)]
3. A material that is reported as complying with the pass/fail criteria of ASTM E136 when tested in accordance with the test method and procedure in ASTM E2652.  [101:4.6.13.1(3)]

Fiberglass Reinforced Polymer (FRP) materials can meet the following minimum standards for flammability:

• ASTM E84:  Standard Test Method for Surface Burning Characteristics of Building Materials:  Flame spread 25
• ASTM D635:   Standard Test Method for Rate of Burning and/or Extent and Time of Burning of Plastics in a Horizontal Position:  Self-extinguish
• UL 94 Tests for Flammability of Plastic Materials for Parts in Devices and Appliances:  V-0

Can this material be considered an equivalent to non-combustible material?

​While Fiberglass Reinforced Polymer (FRP) materials have an excellent fire resistance rating under ASTM and UL tests, it is not specifically classified as non-combustible under ASTM E136.

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I have an existing foam/water deluge system covering vessels and sprinklers providing area coverage for pool fires. The sprinklers are smaller than K-5.6. The owner wants us to match the existing sprinklers. 

In your opinion, is this acceptable?

For reference, NFPA 13 (2013) Section 8.3.4:
8.3.4 Sprinklers with K-Factors Less than K-5.6 (80).
8.3.4.1 Sprinklers shall have a minimum nominal K-factor of 5.6 (80) unless otherwise permitted by 8.3.4...
8.3.4.2 For light hazard occupancies not requiring as much water as is discharged by a sprinkler with a nominal K-factor of K-5.6 (80) operating at 7 psi (0.5 bar), sprinklers having a smaller orifice shall be permitted, subject to the following restrictions:
(1) The system shall be hydraulically calculated.
(2) Sprinklers with nominal K-factors of less than K-5.6 (80) shall be installed only in wet pipe sprinkler systems or in
accordance with the limitations of 8.3.4.3 or 8.3.4.4.
(3) A listed strainer shall be provided on the supply side of sprinklers with nominal K-factors of less than K-2.8 (40).
8.3.4.3 Sprinklers with nominal K-factors of less than K-5.6 (80) shall be permitted to be installed in conformance with 11.3.2 for protection against exposure fires.
8.3.4.4 Sprinklers with nominal K-factors of K-4.2 (57) shall be permitted to be installed on dry pipe and preaction systems protecting light hazard occupancies where piping is corrosion resistant or internally galvanized.

NFPA 15 (2017) Section 7.3.3. Flammable and Combustible Liquid Pool Fires
Water spray systems designed to control pool fires resulting from a flammable or combustible liquid spill fire shall be designed to apply a net rate of not less than 0.30 gpm/sqft of protected area.

I think my new design will require nozzles spaced at 100 square feet if the k-factor needs to be smaller than k-5.6 under NFPA 13.

Also, do you know of any non-aspirating nozzles that are listed for foam?

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Well? What do you think?

Is it a "Sprinkler" or a "Sprinkler Head"?

[Editor's note: there's nothing like a nice Friday release of all that pent-up virus frustration, right!? Have a safe & great weekend everyone]

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Would a mechanical penthouse be considered a “story” in terms of the 30-ft. standpipe threshold?

If the mechanical penthouse is not occupied, does it still apply for the 30-ft limit? Although that would be logical, I can’t the word “occupied” used anywhere except related to high-rise.  I suppose a mechanical penthouse could be considered a mezzanine, I see some commentary that a mezzanine should be no more than 1/3 of the related floor.

The project has three floors where the top classroom floor is 28 feet above fire department access.  But, there’s a mechanical level above that is much higher. It’s accessible, is it a “story” in terms of standpipe?  It would seem logical that this penthouse doesn’t count.  But I’m not 100% sure code backs me up on this.

Of course the thing that bites us, is whether or not the standpipe is manual or automatic – we have fond this to be totally up to the discretion (sometimes whim), of the AHJ.  Sometimes based on good reasoning, sometimes it has causes the unnecessary (IMHO) requirement for a fire pump.

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I had thought the presence of the elevator itself does not necessarily require a sprinkler system if the building does not require a sprinkler system.

For example, if a two-story, type II-B, Business (B) Occupancy building is under 23,000 sqft, the IBC does not require a sprinkler system to be installed. Therefore, the hoistway or the EMR would not require sprinklers.

I’ve had elevator designers argue that the presence of hydraulic fluid requires sprinklers.

I disagree, however; hydraulic fluid is typically a Class III-B flammable liquid. In the example above a two stop elevator would have less than 1000 lb (~150 gal) of hydraulic fluid which does not trigger any Hazardous Occupancy as the control area volume limit for closed-use systems is 13,200 gallons.

Is this the correct approach to take? Does the presence of the hydraulic fluid or any other component of an elevator trigger sprinkler requirements for the rest of the building?

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I have to do a sprinkler design for an MRI room and I need all the hangers and sway brace components to be non-ferrous material.

Where can I finds non-ferrous components for hangers and sway brace?

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We have a 2-hour fire rated stair enclosure. The stair landings and stairs are built with wood but are covered with drywall and gypcrete. 

Is this considered a combustible stair requiring sprinklers at every landing?

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My employer owns several properties in with 2 fire pumps that are discharging to the same loop. The pumps were there when we bought the buildings.  In most cases there is one electric and one diesel, but in other cases there are two diesel fire pumps.

The power purveyor is not considered unreliable by any criteria.

Is there anything you can think of that would prohibit me from decommissioning a redundant pump for the purpose of saving on maintenance costs?

Each pump is 2000 gpm and the greatest demand on the loop is less than 3,000 gpm. The pumps are provided in parallel. 

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Hi there, just reviewing NFPA 13 for the number of Fire Department Connections allowed on any one building.

I see NFPA 13 16.12.5.6 indicates that sign is required if an FDC only serves a portion of the building. Does it state that only one FDC per building is allowed, or can you have multiple FDC's on one building? Thank you.

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We are looking at a boat storage facility in the northeast. The facility is 42-ft high storing fiberglass boats. It's unheated. The owner doesn't want in rack sprinklers, nor does he want a fire pump.

What would be the fire sprinkler design criteria for this type of facility?

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I'm working on a project with a very extensive horizontal standpipe; it is about 2000 feet long and in a loop, so almost 5,000 linear feet when all said and done.

Where can I find guidance on providing expansion joints?

Due to the system being so long, we're worried about providing some flexibility in the instance of extreme temperature swings (Virginia). Would seismic flexible joints be appropriate?

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Sorry if this is too location-specific, but I have a question I'd like to get other designer/engineer input on. The Chicago Building Code (Section 15-16-600) specifically has their own density/area requirements, with a minimum of 0.10 gpm over 1,500 sqft for NFPA 13 applications.

Does this mean that they do not accept residential sprinklers (most demanding 4 adjacent residential sprinklers)? Do they also not accept the area reductions for quick-response sprinklers?

Based on the requirement in the code they certainly have the ability/right to override NFPA 13, I just haven't seen any other jurisdiction overrule the allowances in NFPA 13 and was curious if this holds up for other installers in the area.

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A question for the pump experts on the forum; the line of horizontal split-case fire pumps I'm familiar with generally come as 1770 RPM or 3560 RPM.

What is the benefit to using one versus the other? Do contractors generally have a preference? Is cost, sounds, wear-and-tear impacted by the RPM selection? Thanks in advance.

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During a hotel stay in NYC over the weekend I noticed the combination standpipe included a 3" pressure reducing valve just upstream of the 3" zone control assembly.

An indicating valve was not installed on the inlet side of the Cla-Val (model 90G-21 with no pressure gauges). A filler piece between the PRV outlet and the butterfly valve included a pressure gauge which was at 60 psi. The 2-1/2" fire hose valve was standard pressure and the express drain was only 2".

This arrangement is not something I would expect to see in the DC metro area, but is it typical of NYC?

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We have a combination sprinkler/standpipe riser through floor-level landings in a stairwell of our building. There is a project requirement to provide a pipe sleeve and "required clearance per NFPA 13". 

NFPA 13 gives very clear guidance on clearances in Section 9.3 (NFPA 13 2016 Edition), but that doesn't apply to this project as it is not required to be designed for seismic (Seismic Design Category B).

Where can I determine what clearance needs to be between the pipe and the hole in the concrete stairwell floors/ceilings? I'm not seeing any clearance requirement, but I surely could be missing something. Thanks in advance!

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Big picture question here - I am working on an airport project. We have a Passenger Terminal Building and Aircraft Stands adjacent to the building.

I need to provide sprinkler protection with fire hose cabinets in the Passenger Terminal Building (1,000 gpm at 8 bar / 100 psi), AND fire hydrants to resupply the aircraft rescue and firefighting trucks (1,500 gpm at 6 bar / 87 psi).

Do both of these demands need to be considered together to size the fire pump (both flows combined)? 

We are considering one duty pump and one standby pump. Thanks in advance.

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NFPA 25 requires a legible Hydraulic Information Sign.

How do I replace a missing Hydraulic Placard (or calculation plate/card) on an existing system? And what if there isn't original design information available?

I'm curious to see how others are addressing this deficiency.

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Wanted to say thank you to all of our community contributors for this past month, and especially those top contributors: