MeyerFire
  • Blog
  • Daily
  • Exam Prep
    • CFPS Tools
    • NICET Tools
    • PE Forum & Errata
    • PE Problems
    • PE Store
    • PE Tools
    • PE Prep Series
  • TOOLS
    • TOOLKIT (FREE TRIAL)
    • *TOOLKIT (PURCHASE)
    • SUBMIT AN IDEA
    • BACKFLOW DATABASE*
    • CLEAN AGENT ESTIMATOR
    • CLOUD CEILING CALCULATOR
    • DOMESTIC DEMAND
    • FIRE PUMP ANALYZER
    • FIRE PUMP DATABASE*
    • FIRE FLOW CALCULATOR*
    • FRICTION LOSS CALCULATOR
    • HANGER SPACER
    • IBC TRANSLATOR*
    • K-FACTOR SELECTOR
    • NFPA 13 EDITION TRANSLATOR ('19 ONLY)
    • NFPA 13 EDITION TRANSLATOR ('99-'19)*
    • LIQUIDS ANALYZER*
    • OBSTRUCTION CALCULATOR
    • OBSTRUCTIONS AGAINST WALL*
    • PLUMBING FIXTURE COUNTS
    • REMOTE AREA ANALYZER
    • QUICK RESPONSE AREA REDUCTION
    • SPRINKLER DATABASE*
    • SPRINKLER FLOW*
    • TEST & DRAIN CALCULATOR
    • THRUST BLOCK CALCULATOR
    • TRAPEZE CALCULATOR
    • UNIT CONVERTER
    • VOLUME & COMPRESSOR CALCULATOR
    • WATER SUPPLY (US)
    • WATER SUPPLY (METRIC)
  • CODE CALLS
  • LOGIN
  • STORE
  • About
Picture
A FORUM FOR FIRE PROTECTION QUESTIONS & PE EXAM PROBLEMS | SUBSCRIBE NOW

Storage Capacity for Existing OH Pipe Schedule?

10/12/2020

8 Comments

 
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.

​​​​​​​​​​​​​​​​​​​Submitted anonymously and posted for discussion. Discuss This | Submit Your Question | Subscribe
8 Comments
Dan Wilder
10/12/2020 08:41:58 am

Let's not forget the OH3 curves. The old curves used to be ".1" ".18", ".24", & ".30" for the 1500 square foot design areas (understanding that this isn't a hydraulic question but Ordinary Hazard had a third option for a time).

My question is what changed to bring you in to perform work? If the owner was being questioned by the AHJ as to system capability (with no modifications ongoing), then I would write up your findings stating the system does not work per current standards (design area & density + current water supply).

If you have a calc plate or system as builts, then the allowable design criteria should be available and the capabilities/limitations of the system need to be maintained (unless your AHJ has outright struck the IFC/NFPA references to use of pipe schedule systems). Without the original system design, the safest non-calculation method would be the approach you mentioned of the lowest OH design available. Luckily, the LH & OH pipe schedules are well defined and not an issue to prove intent.

Beyond that, to evaluate the system would require current NFPA guidance and, as you stated, the system does not work as currently configured.

Reply
Noah Koski
10/12/2020 10:10:07 am

Hey Dan, good questions. The occupant of the space is changing and the new occupant intends on storing a different commodity in a different configuration than the previous occupant. The AHJ typically makes us verify the existing system is adequate for a new occupant when they pull a building permit with new rack plans.

The building owner is the 3rd owner of the building since 1973 so there are no as-builts or hydraulic placards. The pipe schedule of the existing system is a textbook OH pipe schedule. It sounds like OH1 would be the safest storage capability to communicate to the building owner since the system does not work hydraulically.

Reply
Dan Wilder
10/12/2020 10:32:17 am

Yes, with no info the OH1 (Class 1 to <12' & Class 2 to <10' - nothing else) approach would be the safest with the caveat that you provide something in the letter stating that hydraulic calculations to current standards would be in the best interest of all parties and that your review/conclusion is only at a basic level of compliance as to the original design intent and per NFPA (site sections and adoption year).

If he pulled a rack permit that is a little worrisome.

Mike
10/12/2020 10:48:14 am

If you are saying you calculated the system for OH1 and there wasn't enough pressure, why would you stay with OH1 storage capabilities. You now have prior knowledge of an inadequately designed system for a new/changed occupancy.

Wouldn't this become a liability to your company in case of a fire?

If it were me, I'd present it to the new owner. There is also the insurance underwriter that may want plans and calculations.

I have done some of these reports and the owner has had to upgrade the system to comply with the occupancy when the existing system was deficient.

Reply
Casey Milhorn
10/12/2020 12:15:26 pm

Dan has some great info and good points and I would definitely approach it as Mike is suggesting. I have done a number of these and you have to put on your lawyer hat first. You do not want to be sitting on the stand being grilled by a lawyer 5, 10, 30 years down the line for something you did or did not do. My letters always state the info I received, where I got it from, the date I got it, and the 2nd part of my letter is analyzing existing storage (hopefully classified by owner, you don't want to do that for them if at all), 3rd part is analysis of what the system is capable of doing, and then the last part is the conclusion of if it works, or if it doesn't. Be very clear that water supplies can and do change over time, any information supplied by others is assumed accurate, and that you will not be liable for changes in occupancy/storage heights/storage types/storage scenarios, that could affect the system's capability of proper protection. In my opinion, this is not something you want to half A do. Be very clear of your scope, what you are doing, and then be very detailed. Or wash your hands early and put it back on owner. Don't get caught playing in the middle of the road on something like this. You should always assume its not if there is a fire event, but when will there be a fire event at this location.

Reply
Franck
10/13/2020 10:45:43 am

I fully agree with Mike's comments.

Working for an insurance company for more than 25 years, I would definitely require an upgrade of the sprinkler system.
With the information you provided, if this is a correct understanding from my side:
- you have a pipe schedule system for OH
- when you do calculations, you can not achieve the demand for OH (in that case, your system is actually not an OH, but something weaker... maybe LH ?)
- the new owner want to install racks... and you know that in rack storage you may find in the future very different adverse conditions than what they ware approved (with your system, you will limit both the commodity classification and the height of storage... but everybody knows that if more plastic need to be stored, it will be stored, and if you can store higher, you will store higher...).

I would call this a scary situation...

In you case (again, as an insurer's point of view), the question is "will you be confident that a fire in the new configuration will be controlled". So far, I am not convinced. And the AHJ would probably be not convinced either.

Reply
Noah Koski
10/13/2020 12:10:47 pm

NFPA 13, 2016 section 11.2.2.3 allows pipe schedule methods for additions or modifications to existing pipe schedule systems. If the water supply requirements of Table 11.2.2.1 are met, why would the system need to be modified if the maximum storage is kept to the OH1 storage limitations. NFPA 13, 2016 doesn't provide any guidance on upgrading existing pipe schedule system based on hydraulic calculations except for Extra Hazard occupancies. I hear what you're saying from an insurance perspective, but that sounds like an opinion above and beyond the standards of NFPA 13, 2016 since there is nothing that recommends doing that. The hydraulic calculations were for the owner, but doing calculations doesn't change the fact that pipe schedule systems are allowed. My understanding is that most pipe schedule systems don't work hydraulically. If the intent is to upgrade a system every time someone decides to try a hydraulic calculation (knowing that it probably won't work), why would NFPA 13, 2016 11.2.2.3 allow the pipe schedule method to be permitted?

Reply
Casey Milhorn
10/13/2020 12:41:22 pm

I would have to agree with Franck as well on this. The question is how many pipe scheduled systems have not had any changes on what is being stored, how its being stored, the height, etc... it comes down to who has asked for this "analysis" and why. Also remember that an ordinary hazard occupancy is not the same as a storage occupancy using ordinary hazard density and area for protection. There are some nuances there that you should be very careful of making from Chapter 11 to Chapter 13, or vice versa. Like 11.2.2.1 water supply requirements mention light or ordinary hazard occupancies, they don't mention storage occupancies protected by ordinary hazard design requirements. Little bit of a rabbit hole there. Now that you have proof that the system doesn't work hydraulically (even if you didn't do an analysis of storage type, height, arrangement, etc..) you are in a precarious position.

Reply



Leave a Reply.

    Jump to: Daily Posts
    Jump to: PE Problems
    Picture
    Why Sponsor?

    Free Signup

    Subscribe and learn something new each day:
    I'm Interested In:

    Community

    Thank You to Our Top
    ​October '20 Contributors!
    1. SK
    2. Franck
    3. Dan W.
    4. Jonathan ​5. Casey M.
    6. Sean
    7. Colin L.
    8. Mike
    9. Jonathan J
    ​10. Daniel G.


    Your Post

    SUBMIT A QUESTION

    The Toolkit

    Sprinkler Designer or Engineer?
    ​
    ​Get all of our tools, including the Sprinkler Database, Friction Loss Calculator, Fire Pump Analyzer and more:
    Picture
    FREE 30-DAY TRIAL
    GET THE TOOLKIT

    Filters

    All
    ABA
    ADA
    ASCE 7
    ASME A17.1
    Daily Discussion
    Design Documents
    Explosion Protection & Prevention
    Fire Detection And Alarm Systems
    Fire Dynamics
    Flammable & Combustible LIquids
    FM Global
    Human Behavior
    IBC
    IFC
    Information Sources For Analysis
    IRC
    Means Of Egress
    NFPA 1
    NFPA 10
    NFPA 101
    NFPA 11
    NFPA 110
    NFPA 12
    NFPA 13
    NFPA 13D
    NFPA 13R
    NFPA 14
    NFPA 15
    NFPA 17A
    NFPA 20
    NFPA 2001
    NFPA 214
    NFPA 22
    NFPA 24
    NFPA 25
    NFPA 291
    NFPA 30
    NFPA 400
    NFPA 415
    NFPA 497
    NFPA 5000
    NFPA 502
    NFPA 54
    NFPA 70
    NFPA 72
    NFPA 92
    NICET
    Passive Building Systems
    PE Prep Guide
    PE Prep Series
    PE Sample Problems
    Poll
    Smoke Management Systems
    Special Hazard Systems
    Types Of Analysis
    UFC 3 600 01
    UFC 3-600-01
    Updates
    Water Based Fire Suppression
    Weekly Exams


    Archives

    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    November 2016
    October 2016
    July 2016
    June 2016
    June 2015


    Daily
    Daily discussions are open-ended fire protection, fire alarm, and life safety questions submitted anonymously for the benefit of sharing expertise and learning from other perspectives. Anyone can submit a question here:
    SUBMIT A QUESTION

    Exam Prep

    Picture
    2020 PE Prep Guide​
    ​(Available Now!)
    Picture
    PE Prep Series
    ​(Available Now!)
    2020 PE Prep Series
    Current Leaderboard
    ​(Click to enlarge)
    Fire Protection PE Exam Prep

    PE Problems
    ​Visit July-October for daily Fire Protection PE Exam sample questions.

    Solutions are posted the day after posting.

    Comment with your solutions, questions or clarifications.

    Please note that questions posted are unofficial and in accordance with NCEES rules are intended to be similar to actual exam questions, not actual exam questions themselves.

    RSS Feed

Home - About - Blog - Contact - Exam Prep - Store
Picture
Copyright © 2020 MeyerFire, LLC
The views, opinions, and information found on this site represent solely the author shown and do not represent the opinions of any other party, nor does the presented material assume responsibility for its use. Fire protection and life safety systems constitute a critical component for public health and safety and you should consult with a licensed professional for proper design and code adherence. Some (not all) outbound links on this website, such as Amazon links, are affiliate-based where we receive a commission for orders placed elsewhere.
  • Blog
  • Daily
  • Exam Prep
    • CFPS Tools
    • NICET Tools
    • PE Forum & Errata
    • PE Problems
    • PE Store
    • PE Tools
    • PE Prep Series
  • TOOLS
    • TOOLKIT (FREE TRIAL)
    • *TOOLKIT (PURCHASE)
    • SUBMIT AN IDEA
    • BACKFLOW DATABASE*
    • CLEAN AGENT ESTIMATOR
    • CLOUD CEILING CALCULATOR
    • DOMESTIC DEMAND
    • FIRE PUMP ANALYZER
    • FIRE PUMP DATABASE*
    • FIRE FLOW CALCULATOR*
    • FRICTION LOSS CALCULATOR
    • HANGER SPACER
    • IBC TRANSLATOR*
    • K-FACTOR SELECTOR
    • NFPA 13 EDITION TRANSLATOR ('19 ONLY)
    • NFPA 13 EDITION TRANSLATOR ('99-'19)*
    • LIQUIDS ANALYZER*
    • OBSTRUCTION CALCULATOR
    • OBSTRUCTIONS AGAINST WALL*
    • PLUMBING FIXTURE COUNTS
    • REMOTE AREA ANALYZER
    • QUICK RESPONSE AREA REDUCTION
    • SPRINKLER DATABASE*
    • SPRINKLER FLOW*
    • TEST & DRAIN CALCULATOR
    • THRUST BLOCK CALCULATOR
    • TRAPEZE CALCULATOR
    • UNIT CONVERTER
    • VOLUME & COMPRESSOR CALCULATOR
    • WATER SUPPLY (US)
    • WATER SUPPLY (METRIC)
  • CODE CALLS
  • LOGIN
  • STORE
  • About