Still in the design phase for a new dry pipe fire sprinkler system retrofit into an existing attic space. Due to the existing arrangement of the building it may be significantly easier to route a portion of the system exposed to the outside. 

My only concern with doing so, along with ensuring that the exterior of the exposed pipe is well protected, would be the potential difference in temperature between a cooler outside and a potentially much warmer attic.

Would condensation not build-up when the cooler outside cools the pipe as it enters the warmer attic?

I may be overthinking this, but how best could I address potential condensation concerns in a scenario like this?

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What do you recommend as the best route when routing fire sprinkler branch pipe for projects with open-web joists?

Advantages (to me) to routing within joists can be higher ceiling elevations, potentially avoiding conflicts with ducts or other systems, and potentially allowing higher clearances below the pipe for vehicles or moving equipment.

Disadvantages (to me) seem to include the difficulty of getting the pipe up and into the joist (depending upon the length of the pipe and the opening size in joists), potentially mis-aligning joists that can't allow a straight run, and potentially running into solid girders if all of the structure isn't open-webbed.

What are your thoughts?

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A basic question from a non-ITM guy: is the hydrostatic 200 psi or 50 psi over working pressure test simply achieved by hooking up a mobile pump to the system and gauging for pressure loss and visual leakage?

I have not witnessed one of these myself, and wondered if a system design usually would incorporate an extra small outlet for this test or if it's just connected to a main end-cap or something similar.

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I was needing a little help validating the methodology for fire flow requirements in my city. They do not allow you to verify fire flow per a fire hydrant flow test.

Our city always uses hydraulic calculations (a hydraulic model) to determine acceptable flow in an area. However, in their hydraulic model they always assume that the water usage that day is 19,000,000 million gallons which was established by taking the highest usage in the history of our community of all time, which occurred in 2012 when we had 30 plus days of 100 degree weather of 18M gallons and adding a 1 Million to that. Our average daily usage in our community is around 10 to 11 million gallons per day.

Anyway, the local engineers say that methodology is consistent with the International Fire code. What are your thoughts? I would love to understand what the IFC requires.

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Residential single-family dwelling is getting an NFPA 13D sprinkler system with a pump and water storage tank. 

Is the test line required to be routed to the exterior, or can it be run back to the water storage tank? I've seen it both ways but don't see an applicable code section.

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We have a machine room-less elevator where the motor is located on top of the elevator cab and the elevator equipment is located within the elevator shaft.

NFPA 13 (2016) 8.15.5.3(2) allows sprinklers to be omitted from the hoistway of "traction elevators" where the hoistway is "protected by smoke detectors, or other automatic fire detection installed in accordance with NFPA 72", and several other requirements.

NFPA 72 (2016) 21.3.3 states that only the elevator hoistway and elevator lobby smoke detectors or other automatic fire detection (as permitted by 21.3.9) shall be used to initiate Phase I Emergency Recall Operation. 

NFPA 72 (2016) 21.3.9 states that if "ambient conditions prohibit installation of automatic smoke detection" that other automatic fire detection initiating devices shall be permitted.

What type of ambient condition in an elevator shaft would qualify as prohibiting smoke detection? 

I understand smoke detectors in elevator hoistways can cause nuisance alarms (NFPA 72 2016 A.21.3.9) and are very difficult to test and replace within elevator shafts, so in my opinion a heat detector would be better for elevator recall in the shaft if it's allowed by code.

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Does anyone have experience with a mamava (mobile lactation room/pod) being placed in a commercial business occupancy?

The square footage is approximately 50 sqft. It is composed of only Class A rated materials (flame spread index).

From a practical perspective it does not make sense to me to drop a sprinkler in. However, I'm hard-pressed finding an exemption from code (NFPA 13 or 101) to not sprinkler the space since it's inhabitable and not a bathroom or closet (which I know they are exceptions for sprinklering based on size). 

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We have an AHJ that is requiring a sprinkler be located in a grease exhaust duct - but I'm finding it difficult to see where this would be required (reviewed NFPA 96 and 13).

The duct serves a Type I kitchen hood, has an Ansul suppression system, and then has a roughly 45 foot run to exhaust to the outside. We haven't come across a requirement for a duct run like this before, is it required?

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Does anyone have a good resource for determining audibility loss (dB loss) through various door types? I recall seeing a reference chart that was perhaps printed in a fire alarm handbook in the 90's, but I don't have a copy.

​Intelligibility is a world all on it's own - if we need intelligibility I typically locate a speaker on the opposite side of closed doors (private offices, for instance). Is there a way I can model or predict intelligibility through closed doors? I've tried Ease EVAC years ago using door gaps, but it wasn't well suited to model the losses at that time.

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A garage within a small commercial building has radiant heat only. Since radiant heaters do not warm the air but rather only any physical object that is in the direct path of heat transfer, I've never relied upon them for maintaining correct temperature around a fire sprinkler system.

Have you used radiant heat to maintain temperature in a wet system? NFPA 13 (2016 Edition) 8.16.4.1.1 calls for temperature reliably maintained at or above 40 degrees F (4 deg C) for a wet system, which I would not believe would be the case for radiant heat.

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Where can I find information on how much flow each type of fire department connection can handle (siamese, 4" Storz, or 5" Storz)? Is this provided in a standard, or manufacturers data? 

Also, does just about every fire department have the ability to connect to Storz? I've heard from many departments that the FDC type depends on the flow of the building, which leads me to believe that many departments can connect to any type of FDC.

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I work for an engineering consultant and we often do work directly with university and healthcare clients that expect an estimate as part of the deliverable package.

I typically track square footage costs whenever I receive them (on past projects), but even that is rare. I've since transitioned to using RS Means unit cost pricing and adjusting for location and historical cost increases.

For others doing cost estimation, have you found relative accuracy using RS Means? Are there other estimating providers that are better suited for cost estimating in our industry?

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Does anyone have successful experience with routing a fire sprinkler drain and/or inspector's test to a mop sink? 

I have a client that has a 12" deep mop sink in a janitor's closet which the contractor is asking to as the discharge for an inspector's test. I suspect that with the pressures on the system (~120 psi) and a typical 1/2" orifice, that the flow will be roughly 60 gpm (=5.6 x sqrt (120)). We are recommending a 4" plumbing standpipe to accept the inspector's test if a drain riser can't be routed to the exterior separately. What are your thoughts?

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We traditionally have specified closed wye-delta transition starters for electric fire pumps on our projects. The fire pumps typically consist of horizontal split-case electric pumps between 500 and 1,500 gpm.

In the past, we've felt that the closed wye-delta starter offered a good balance of cost (less than soft-start but more than open delta wye) against the impact it has on backup generator sizing (helps generators size more than an open-wye delta but not as much as soft start). 

Is soft-start still significantly more expensive than delta-wye closed transition starters?

I am hearing that the cost of soft-starters may have come down significantly and we try to be open-minded to what the industry is offering if we're in the wrong.

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For hydraulic safety factors (such as in fire sprinkler systems), determining whether a 5 psi safety factor is met in a design is easy. The Available Pressure must be greater than Required Pressure + 5 PSI.

However, for percentage safety factors such as 5% or 10%, is the percentage calculated based on the Required Pressure or Available Pressure? 

As an example, if we have a system that requires 80 psi and the available city pressure of 88 psi, a 10% safety factor on the required pressure would be 80 psi x 10% = 8 psi safety required. In this case the minimum is met. However, a 10% safety factor on the available pressure is 88 psi x 10% = 8.8 psi safety required. In this case, the safety factor is not met.

This is an extreme example, but I'm curious what others would use when looking at determining safety factors.

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You all rock! Thanks for helping make this space helpful for others by sharing your unique perspectives. Here's the top commenters from March:

A laundry room for a hotel contains large commercial dryers. These dryers appear to have internal fire suppression systems that require a 3/4-inch water hookup with a flexible hose.

Based just on the 3/4-inch threaded hookup and flexible hose, I would presume this connection should be by domestic water, but I wanted to ask if anyone provides connections like these from the fire sprinkler system?

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I'm working on an 1880's masonry four story historic building that currently has no fire sprinkler system. We're looking to retrofit a fire sprinkler system and we're looking into any and all ideas for concealing the pipe but keeping the historic charm. 

This building itself has concrete beams with 'tin' ceilings in-between. We're considering building down false beams, furring out entire walls, and potentially soffits to help conceal pipe. 

For those who have complete sprinkler retrofit designs for historic buildings, what tips or methods have you used to make your projects successful?

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Other than the Contractor's Material and Test Certificate for Aboveground Piping (NFPA 13) and System Record of Completion (NFPA 72), where can I find a good procedures for acceptance testing for fire sprinkler and fire alarm systems?

​Is there a step by step approach that I can add to for my particular project?

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There's likely to be a wide perspective on the value of engineer-provided sprinkler layouts on plans that delegate the full-design to the fire sprinkler contractor. Do you feel they provide benefit? Take the poll and comment below. 

[Don't see the poll below? Click here.]

A middle school is being expanded by two classrooms and about six small offices and supports spaces. The addition is separated by a fire barrier from the main school, and the existing school has a temporal-3 horn/strobe fire alarm system throughout (and is fully-sprinklered).

Current code requires an emergency voice/alarm communication system for the expansion, which the design team intends to provide.

The question is how to address the interaction between the new voice system and the existing? Is this purely and AHJ call?

Ideally, the school should consider upgrading their entire fire alarm system to voice for a cohesive message and best benefit. However, funding is very tight and we're not confident they'll have the support they need to do a full upgrade at this time.

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Have you had AHJ’s request FPE seals on hood fire suppression systems often? It’s in the letter of UFC 3-600-01 (this is a US military project) but has not come up before for us. 

Do you have an opinion on what needs to happen if the system (or the majority of it) is factory installed in the hood? Can it be treated as part of the UL listed assembly?

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A flexible sprinkler armover is serving a sprinkler in a suspended ceiling, and connects through a gypsum wall to the branchline.

Is there anything that prohibits the flexible drop from running through the wall?

Is a clearance required through that wall?

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From Joe: I haven't had as many questions posted recently by members, so if you have a question you'd like to see posted on the Daily forum, email them to me at jdmeyer@meyerfire.com. Thanks & I look forward to hearing from you!