Question about doing hydrostatic testing using compressed gas such as nitrogen rather than using a test pump. Do you know of restrictions to using compressed gas by the standard?

​I know there are “other” safety issues when working with compressed gases. Just asking about using high pressure gas for the acceptance test.

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Sorry - seems to have missed the question posted for this one. If you received a blank email today, my apologies. Now onto the question:

Where can I find guidance as to whether or not an oil transformer requires sprinkler protection? I'm specifically looking into standards or requirements concerning deluge sprinklers for oil transformers. Thanks in advance.

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Does the proximity of a residence and the number of windows on that residence make a difference in which system type is used (between NFPA 13, 13R, or 13D)? What are the restrictions that would impact the system type?

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We have a project which is on a steep slope (the bottom of the site is about 120 feet lower than the top of the site). If we attach a fire main to the bottom of the site, the fire pump we have won't have much issue with keeping the city pressure at a 20 psi minimum or above.

If we attach to the water grid at with the fire service main at the top elevation of the site, we will probably need a suction control valve in order to keep the city pressure at 20 psi at the top elevation since the available water supply is so low.

My question is - if we pull pressure on a city's system at the low elevation, do we have to chart and consider the rest of the water supply network?

There's a chance if we pull the water supply down to 20 psi at the lower elevation that the system at the higher elevations would be well below the 20 psi due to elevation pressure loss. Thanks for your input!

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Is the travel distance requirement for fire extinguishers in NFPA 10 measured like means of egress travel distance, or "as the crow flies"?

I've seen plans recently that just have a 75-foot radius around an extinguisher proving coverage and wasn't sure if that's the proper way to measure travel distance for extinguishers.

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My daughter is in fifth grade this year and will be picking out a science fair project.

She really wants to choose a topic relating to fire sprinklers. Obviously, I'm doing everything I can to support this.

I'm wondering if anyone out there might actually know of sprinkler-specific science fair projects that have been done in the past? Or maybe some ideas? Thanks!

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Just wanted to wish each of you taking the PE Exam tomorrow all the best of luck.

I've enjoyed putting together these daily questions, the prep guide, and the online prep series and I very much hope that they've been helpful for you!

If you ever have any comments or feedback, feel free to shoot them my way at joe@meyerfire.com. Thanks for subscribing, commenting, and being a part of the community here. All the best in knocking this exam out tomorrow!

What is the max gpm you can get with a 6” dr 18 underground?

We had a flow test of static 68 psi residual 48 psi flowing 1950 gpm. With 3111 gpm @ 20 psi. Some one is telling us the max gpm is 800 gpm. How is this possible?

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A 4-inch schedule 40 main is routed parallel in-between two beams and requires a trapeze hanger. The main is 2 ft. from one beam and 8.5 ft. from the other for a total span of 10.5 ft. What is the smallest schedule 10 pipe diameter capable of supporting this main as a trapeze hanger?
a. 2-inch
b. 2-1/2 inch
c. 3 inch
​d. 3-1/2 inch

Solution | Posted 10/24/19

I am currently dealing with a fire station that was constructed in 1965, prior to any adopted building codes in Indiana.

The fire station suffered structural and roof damage during a storm from a tree fall. My question is an exterior exit staircase from the second floor was damaged. A structural engineer assessed the staircase and addressed the items needing repaired, which is quite extensive and will need to be removed for repair. The staircase is far from meeting current code.

The insurance company does not want to pay for a new exterior stairway that would meet code, they want to have it repaired.

Is there any code requirement in the 2012 IBC that would require this stairway to be brought up to the 2012 IBC on an existing building?

The stairway is the original. I cannot for the life of me find a code section that would require this stairway to be code compliant if removed and repaired. If we can cite a code requirement for this to be code compliant the insurance will pay for a brand new stairway, which is our goal.

Any recommendations or prior experience with this type of situation would be greatly appreciated! (You would think the insurance would want a code compliant exit component, but I know its all about the $$$)

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Determine the flow (in gpm) through an extended coverage pendent K16.8 sprinkler at 85 psi.
a. 52 gpm
b. 155 gpm
c. 348 gpm
​d. 1428 gpm

Solution | Posted 10/23/19

Is it acceptable to place the connection for the fire pump test header on the 'system' side of the isolation valve?

I've seen instances of this and it concerns me that there is a potential to render the FDC ineffective during pump testing; not to mention the possible corruption of pump test data due to the influence of the 'stored' water and pressure in the existing sprinkler system.

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Use Alpert's Correlation to determine the maximum temperature (in degress Celsius) of a ceiling jet at a point 1.3 meters (horizontally) from a 1.8 MW fire which burns within a 2.2 m tall room. Assume an ambient temperature of 22 deg C.
a. 25 deg C
b. 78 deg C
c. 326 deg C
​d. 384 deg C

Solution | Posted 10/22/19

Here's this week's Prep Series leaderboard and the final one for the 2019 PE Prep Season. Be sure to check back this week for the plaque award winners that's based on the total season scores that have accumulated from each week. 

I'm designing a system with sprinklers at the ceiling of a large open space. There is a vestibule within this space that has a lower ceiling that requires 3 sprinklers. The client does not want pipe drops or hangers above the vestibule to be visible from the rest of the open space.

The proposed solution is to run a branchline down the wall and horizontal tight to the ceiling. Is there a good way to support this that meets the requirements of NFPA 13 chapter 9? The vestibule has CMU walls and metal stud ceiling.

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Solution | Posted 10/21/19

A building owner has bought a large old warehouse and in about 6-8 months will convert it into educational spaces. They've asked if over the winter they could drain down the large wet sprinkler system as they aren't planning on heating the space or occupying the building during that time. 

I recommended against it since they'd be without protection during that entire time and a fire could result in a total loss of the building. 

I also suggested they speak with their property insurer, couldn't store anything in the building, and would need to talk with the fire department as it would be a system impairment.

Aside from that, what other barriers would they come across? What would you have recommended?

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Solution | Posted 10/18/19

This project is a residential occupancy (dormitory) with a sprinkler system designed under NFPA 13. The contractor is using residential-style sprinklers within each unit, but standard-spray sprinklers in the corridor.

The corridor has these standard spray sprinklers just off the main which runs down the corridor. The contractor has provided calculations for the four most demanding adjacent residential style sprinklers, which is fine. He's also provided a calculation for the corridor using five sprinklers.

NFPA 13-2016 11.2.3.4.2 states:
11.2.3.4.2 Where an area is to be protected by a single line of sprinklers, the design area shall include all sprinklers on the line up to a maximum of seven. 

Since the corridor's sprinklers are not residential, how many sprinklers should be calculated in the corridor?

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Solution | Posted 10/17/19

This is giving me heartburn. A clothing manufacturing company wants to store group IV commodities.

16.1.3 Movable Racks. Rack storage in movable racks shall be protected in the same manner as multiple-row racks.

16.2.1.2 Protection Criteria for Rack Storage of Class I Through Class IV Commodities Stored Up to 12 ft in Height.
​
16.2.1.2.1 The protection criteria for storage up to and including 12 ft shall be the same as miscellaneous storage from Chapter 13.

The definition of Compact Storage Module does not specify passive protection to qualify as such.

My question is: “Is it correct to treat this rack configuration as moveable racks?”

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Solution | Posted 10/16/19

Have a flow test in a semi-rural area that has static pressures of over 130 psi but a residual pressure of 60 psi at just 500 gpm.

A flow test from nearly a decade ago shows worse results - with a static of around 120 and a residual of 20 psi at just 600 gpm.

My initial concern with the older flow test was a partially-closed valve or obstruction in the line. 

With the newer test the residual pressure seems more reasonable, but other than something being wrong with the system is there a reason that would justify a residual pressure less than half the static at only 500 gpm of flow? Perhaps a system fed with small pumps and no tower? What are your thoughts?

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Solution | Posted 10/15/19

​Want to join in? It's not too late - the PE Prep Series is the ultimate PE Prep tool. It's a series of 1-hour, 10-question simulated PE Exams offered weekly with solutions immediately following each exam. Learn more here. ​​​​Every week of the series is retroactive so you can still test yourself with past week exams