We are designing a residential building that will have a manual wet standpipe in a fully-sprinklered building. The building itself is less than 75-feet high.

I need to calculate the wet manual standpipe but would like to check my approach. 

Do I need to calculate the remote standpipe at the two most remote hose valves at 100 psi, 250 gpm each, plus one more hose valve closer to the source at 250 gpm all the way back from a supply at the fire truck?

​Thanks in advance for any feedback.

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I have a question regarding the need to provide electrical classification for a building using Class 1A flammable liquids.

For this building, 4 gallons could be out in use (located anywhere in the building). The MAQ is 10 gallons. I have discussed this with NFPA 30 committee, the manufacturer, and the AHJ (who is a knowledgeable FPE). They have all determined that even if the MAQ is not exceeded, electrical classification is required if a flammable/explosive mixture could be present.

The NFPA 30 staff directed me to a provision in NFPA 497, Section 5.5, that if the materials will not reach 25% of the lower flammable limit (LFL), this could be utilized to justify not providing classified electrical fixtures.

Does anyone know how to do this calculation, or know of firms that can be hired to do this?

I am an FPE and do not know how to perform it, and I have spoken with other FPE’s who also are not aware. The gentleman I spoke with at NFPA 30 agreed it would be by an industrial hygienist or a chemical engineer and not an FPE.

But does anyone know any that can be hired for a one-off calculation, or have a place where I could learn how to perform it myself (NFPA reference, SFPE article, course, etc.?).

Thank you!

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We have an existing building were the highest occupied floor is less than 30'-0 above fire vehicle access. This building is being renovated.

Part of the renovation involves the construction of a new building to be connect to the existing building. The new building is higher than 30'-0 above fire vehicle access. The exit stairwells in the new building need a standpipe system.

Does the existing building need a standpipe system since it is connected even though the existing building stairways and floors are not higher than 30'-0 above fire vehicle access?​

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We have a project where the general contractor is stating that the vertical penetration in the stairwell landing, where the standpipes are located, need to be sealed.

They are not asking for it to be a fire-rated seal, but they say some sort of seal will be required. I know on past projects this typically was never a requirement. I have searched NFPA and the IBC with no luck on finding something that would insinuate that no seal is required for the vertical standpipes openings within the rated stair.

Is a seal required for these stair landing penetrations?

Any input is much appreciated.

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Are there any drawbacks of testing a diesel-engine fire pump on a main header where other diesel pumps are connected to, instead of a test header?

This is happening in my plant because the test header is is large enough that it would require frequent throttling of test header discharge gate valves for each pump, which has started to wear out and not hold pressure.

Also, what is the minimum flow requirement for weekly diesel pump testing considering the test header doesn't hold? Do we need to run 0%, 100%, and 150% flow test each week?

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For all those who took the October 2020 and January 2021 Fire Protection PE Exam - we hope your experience on the exam was overall positive and you hear good news on your exam score soon.

As the 2020 Prep Series wrapped up last week, we are happy to announce the winners for the 20-week 2020 Prep Series season. The top ten winners will receive plaques like the one below. 

The final standings are computed as the total of all on-time 20-week scores. See the entire final standings here. Thanks and congratulations to all PE examinees on your hard work this year!

Can a split-case fire pump be used with a suction that is below negative 1.5 psi of pressure (below 1.0m)?

Would this be acceptable under NFPA 20?

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We have an account that failed the five year FDC hydrostatic test. The Fire Department Connection is a remote, freestanding FDC. The Fire Marshal is claiming that there is no leakage, however, will not give a pass or fail. 

NFPA 25 (2017) and others reference hydrostatic tests.

6.3.2.1  hydrostatic test 200 psi for 2 hrs or at 50 psi in excess of the maximum pressure where maximum pressure is in excess of 150 psi every five years. (manual standpipe systems and semi-automatic dry standpipe systems, including piping in the FDC)

Annex  6.3.2.1* that mentions a minimum leakage existing under test pressure.

Section 13.8.5 FDC five year hydrostatic testing shall be tested at 150 psi for 2 hrs. There is no mention of minimal leakage allowed.

What is this allowable leakage?

NFPA 24 (2010) Private Fire Mains & Their Appurtenances Section 10.10.2.2.1 requires 200 psi or 50 psi in excess of the system working pressure whichever is greater and maintain that pressure at +/-5 psi for 2 hrs.

Is that my allowable leakage, so that if we lose less than 5 psi or gain no more than 5 psi for 2-hours, that we pass? Wasn't sure if the existing 5-year hydrostatic for underground has leakage that is measured differently from an inside hydrostatic test.
 
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A theater has aisles serving its main seating area. One of the aisles has a stair 51 inches wide, with a wall and handrail on one side and fixed seating on the other. If the handrail has a center-line of 4 inches from the wall, what is the effective width of the stair?
a. 37.5 in.
b. 43.5 in.
c. 45 in.
d. 47 in.

Solution | Posted 10/23/20

I understand that based on most Plumbing Code requirements that black steel pipe is not permitted on the upstream side of a backflow preventer. If pipe is provided between a flange and the backflow, it should be galvanized.

Do fittings, such as an elbow off the flange, need to also be galvanized?

I'm familiar with the Victaulic orange painted cast-iron grooved fittings (Firelock series) as well as ductile iron flanged fittings that seem to be commonly off of a stub-in flange, but I'm wondering if these need anything special like a painted or galvanized finish?

Thanks in advance - really appreciate the community and expertise here.

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Which of the following occupancies have no difference in maximum permitted travel distance for sprinklered versus unsprinklered buildings?
a. Existing Day Care
b. Residential Lodging
c. Existing Mercantile
d. New Business

Solution | Posted 10/22/20

As part of acceptance testing for a fire pump we test the installed pump net pressures at various flows (churn, 100%, 150%) and compare that against the factory certified curve for that specific fire pump. 

For these tests, what is the pass/fail threshold?

What would fail this test, and how far off could the installed pump be to fail this test?

As I understand it, the installed fire pump cannot differ from the factory certified curve more than the error in the measurement equipment (the allowed error in gauges, typically 1% of the gauge reading). I'm not sure if that's the proper way to go about it, but was curious if there's a better pass/fail mark I should be looking for with these tests.

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​A fire pump's speed is altered from 1760 to 1800 rpm. What is the new head if the original was 120 ft?
a. 115 ft.
b. 123 ft.
c. 126 ft.
d. 128 ft.

Solution | Posted 10/21/20

Can you explain what a wall hydrant is used for, and where they would typically be needed?

There are some in older office buildings here in Massachusetts where things freeze.

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​Which of the following is typically not considered obstructed construction for fire sprinkler design?
a. concrete tees with solid members 5 inch wide and 2 ft tall
b. heavy timber construction with 4 inch solid wood beams
c. beam and girder construction with 6 inch steel beams 6 ft apart
d. panel construction with panels under 300 sqft

Solution | Posted 10/20/20

Last week was week twenty, the final, of our 2020 PE Prep Series - it's 20-weeks worth of mini Fire Protection PE Exams.

If you haven't caught it already, see some thoughts about wrapping up the 2020 PE Prep Season here:  Blog Post

Each week we'll post the leaderboard here with the results of that week's exams. To see full leadership board and more details, visit the PE Prep Series page here.

The Leaderboard lists the top total scores for the most recent three weekly exams for PE Prep Series participants. 
See the entire scoreboard here.
​
For those following along, next Monday we'll reveal the overall 2020 Season Winners.

Adding a new Fire Department Connection to an existing building with a 4-inch combination standpipe and 2-1/2 inch mains feeding each level. The standpipe is significantly farther from the new FDC location; however, the 2-1/2 inch feed main is located closer to the new location.

Is it acceptable to connect the 4" FDC pipe to the 2-1/2" main, or do we need to route the pipe back to the standpipe location?

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​Consider the following fire hydrant flow tests conducted at the same elevation:
   Test A: 75 psi Static, 60 psi Residual at 1,200 gpm
   Test B: 65 psi Static, 60 psi Residual at 1,800 gpm
   Test C: 70 psi Static, 45 psi Residual at 1,200 gpm
 Which of the following is true?
a. Test A would provide better pressure than Test B for a 1,500 sqft Light Hazard sprinkler system.
b. Test A would provide better pressure than Test B for a 3,000 sqft ESFR sprinkler system.
c. Test B would always provide better pressure than Test C for any type fire sprinkler system.
d. Both a and c.

Solution | Posted 10/19/2020

NFPA 110 (Standard for Emergency and Standby Power) Section 7.9.2 requires a fuel oil day tank be provided when the main tank is not close enough to the generator to provide sufficient suction head from the prime mover integral fuel oil pump. A day tank is also required if the engine manufacturer's fuel pump static head limits are exceeded when the main tank is at full fuel oil level.

Section 5.5.3 indicates minimum sizing requirements for the main tank, while other documents have maximum sizing allowances for the day tank.

​I cannot find minimum sizing requirements for the day tank in NFPA 110 or other codes and standards. Can someone point me in the correct direction?

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Determine the required thrust block volume (in cubic feet) for a 45-degree elbow serving a wet 6-inch schedule 10 pipe in sandy silt with a 50% safety factor added. The water within the pipe has a maximum pressure of 140 psi and the block material has a density of 150 pounds per cubic foot.
a. 28 cubic feet
b. 31 cubic feet
c. 44 cubic feet
 d. 63 cubic feet

Solution | Posted 10/16/20

NFPA 13 states the following:

8.16.4.1.5 Water-filled piping shall be permitted to be installed in areas where the temperature is less than 40 deg F when heat loss calculations performed by a professional engineer verify that the system will not freeze.

For some reason I had always thought that Tyco or some other heat trace provider had a program available to perform these calculations. I feel there is a better way than breaking out my old heat transfer book. Our general consensus is that the risk is relatively high with these types of calculations.

I’m sure you been tasked with this before; what is the best approach to going about these calculations?

Some owners require these calculations to be performed to avoid dry-pipe systems in Florida, even though the location of the iso-thermal line would require dry-pipe systems - I feel this essentially puts all the liability on the engineer.

I'd be curious to see how others would normally approach this. In this case we would look to run calculations to justify that a wet-pipe system would be sufficient without any insulation or heat trace. Thanks in advance.

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An opening within a smoke partition for air transfer requires what type of protective device?
a. fire/smoke damper, minimum 45 minute rating
b. fire/smoke damper, minimum 1.5 hour rating
c. smoke damper, minimum 250 F rated
d. smoke damper, minimum 350 F rated

Solution | Posted 10/15/20

I need to label some deflagration vents as "out-of-service" since they are not being maintained properly and are currently not needed from a code standpoint (as the use of the room has changed). We do not want to remove them as the room may be changed back one day depending on research needs.

Does anyone know if there is a code reference that points to the size of the letters or font type for an out-of-service-tag?

In this case a tag is not practical since it needs to go on a flat panel. I know there are such requirements for exit and "no exit" signs, but I'm not aware of any code guidance for out-of-service signs. Thanks in advance for any feedback.

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Which of the following would not require a re alarm system?
a. A new second-floor tenant insurance sales office of 60 people
b. An existing four-story fraternity house of 70 people
c. A single-story 80,000 sqft high-hazard warehouse of 90 people
 d. A new single-story 35,000 sqft Class A department store

Solution | Posted 10/14/20

NFPA 13, 2016 Chapter 11 and Chapter 23 provide information on systems that were designed as a Pipe Schedule System (as defined in Section 3.4.9). Section 11.2.2 and 23.7 provide information regarding "Ordinary Hazard" pipe schedule systems, but the storage capabilities in NFPA 13 are based on specifically Ordinary Hazard Group 1 and Ordinary Hazard Group 2 (specifically referencing chapter 13 in this situation for Miscellaneous storage).

I am working in an existing building with an "Ordinary Hazard" pipe schedule system, what are the storage capabilities of the existing system (assuming it does not adequately calculate)?

I did try hydraulically calculating the system just to see if it would work, but there wasn't enough pressure for the existing pipe configuration. A few people I have talked to agreed to stick to OH1 storage capabilities without any upgrades, but I am looking for formal guidance if anyone knows of any.

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