AHJ wants systems converted to dry or heat installed in buildings (the "what if?")

[SprinklerDesigner2]

The buildings, there is about ten buildings in the complex, are within 10 miles of the gulf coast.

With the exception of small shop office areas the buildings are not heated.

Buildings are rectangular 30,000 to 80,000 sq ft with 24' eave heights of bent metal purlin construction with insulation. Pitch of roof is 1" in 12".

The building is at least 20 years old and to my knowledge the complex has never had issues with freezing. For what it is worth the particular building cited is used to store latex water based paint.

The authority having jurisdiction (fire department) inspected the property and issued the following citation:

Converting to dry or preaction is not possible.

From the 2013 handbook:

8.16.4 Protection of Piping.
8.16.4.1 Protection of Piping Against Freezing.
8.16.4.1.1* Where any portion of a system is subject to freezing and the temperatures cannot be reliably maintained at or above 40°F (4°C), the system shall be installed as a dry pipe or preaction system.

As for this particular location the lowest recorded temperature was -1°F in 1899. Average January low is 40°F while average January high is 61°F.

I suppose anything can happen as was the case in the remarkable cold wave of the 12th-13 February 1899, when an absolute minimum of -17 °F but if this happens where we are at a sprinkler system freeze up in a paint storage building will be the least of our problems. I am at the same latitude and while our 20.000 sq ft shop is unheated we've never encountered freezing conditions inside. Even if it does get really cold outside, cold for me is 17 degrees, it never lasts more than a few hours and over the years nothing inside has ever frozen. In our climate, I recognize this doesn't fly in Minnesota, am I wrong in thinking large floor slabs will radiate enough heat for at least a few hours to prevent temperatures from dropping below 40?

I think the only thing I can tell my customer is Section 8.16.4.1.5 "Water-filled piping shall be permitted to be installed in areas where the temperature is less than 40°F (4°C) when heat loss calculations performed by a professional engineer verify that the system will not freeze." or to install a small unit heater in each building. I think he professional engineer would be the best way to go but a question to those who have encountered this do you think I am whistling Dixie or do I have a reasonable chance that a PE will find the heat in the building will stay at 40 degrees?

I don't want to suggest to the owner he engage the services of a PE if there isn't any chance.

 

[cdafd]

13 says reliably maintained at or above 40

1. For twenty years it has been

2. Have the ahj prove it has not been maintained or will not be maintained at or above 40

3. You could say that for almost any building in your area including an office that may have pipe in the attic area

4. Is the ahj just telling you to do it or other similar buildings in the area???

 

[SprinklerDesigner2]

cdafd,

I know multiple buildings, well over two million square feet, in this area that are fully sprinkled, not provided with heat and never a problem over the past 30 years.

It's situations like this that are exasperating, where does it all end? The coldest temperature ever recorded in the city of Miami was 27 °F (-3 °C) on February 3, 1917 does that mean all the buildings without heat need to be converted to dry systems?

I guess we could park a couple salamander heaters in the corner with instructions to the tenants if it ever gets really cold turn these on. Sounds silly but what is the difference between that and installing unit heaters with on and off switches?

Just this building as far as I am aware. In the meantime everyone has double detector checks exposed to the open air above ground.

So far it's just us being picked on but I can't be sure.

 

[stookeyfpe]

If you tell me where the nearest large city is, I can check the ASHRAE Handbook which has temperature extreme data for many mid-size and all major cities. We employ this data in my town when told that it doesn't get cold here.

 

[SprinklerDesigner2]

Stookey,

Theodore, Alabama which is just southwest of Mobile by maybe 10 miles.

The coldest temperature ever recorded was minus 1 degree F during the "Great Blizzard of 1899".

 

[TravisMack]

When we first had to start using the Darcy Weisbach formula for anti-freeze solutions, a discussion came up as to what do we use for the lowest temp to figure density of the solution and what percent of solution do we need. After several back and forth with various entities, I had a conversation with Ken Isman, PE of NFSA. He stated that we use the chart in Chapter 10 of NFPA 13 that shows the isothermal lines. That was to represent the average low temps in the area. That answer seemed to satisfy the AHJ for the project in question. So, you may try looking at those values and see where you fall with respect to that.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[stookeyfpe]

SD2:

I faxed you the data. The extreme annual dry bulb temperature is 19.0 F. It can freeze in that little town. However, the selected temperature for heating is 30.2F dry bulb. I think you have a valid argument.

 

[SprinklerDesigner2]

Stookey,

Thank you for that even if I do not fully understand how to interpret the table.

The reason I don't think heating is necessary is there's multiple buildings over 1 million square foot of identical building in this area that has been here since the late 1970's and I am unaware of anything ever freezing. Add to that I work in a very similar building that is not heated and even when it gets cold outside (25 F) it never drops below 45 F inside.

I think the way out is for the owner to engage the services of a professional engineer to see if he will write a letter. One million square foot never froze in the past 30 years sounds like a safe bet to me.

 

[cdafd]

is this one person telling you to do it?

I would go a little higher first



There has to be an appeals process, suggest exploring that route

 

[wickedspins]

TravisMack: I have heard someone mentioned that map of isothermal lines in NFPA before. If I look at the isothermal lines (Lowest One-Day Mean Temperatures), then almost all the cities in the US should be using dry-pipe or preaction systems as most cities in the US have Lowest One-Day Mean Temperature less than 32 deg. F.... even more cities with Mean Temperature less than 40 deg. F.

Am I reading that map correctly? If an unheated space is located in Tampa, Florida for example, then I would need to use a dry-pipe system instead of wet-pipe system because according to the isothermal lines, the Lowest One-Day Mean Temperature is about 32 deg. F.?

 

[SprinklerDesigner2]

The calculations are completed and the results are in. It's all good.

Did what any competent layout technician should do and that is I hired a professional to do what I wasn't competent to do.

I have a PE friend and I was able to obtain all the information as to the building construction and R values of walls and roofs. We had a cold snap coming where it dropped to 12 F so the owner hunf 4 thermometers about and the cqoldest it got was 44 degrees inside. I learned how it's done, though I will never try to do it myself, the letter was signed and now everyone is happy including the inspector who wrote the citation. Best $740 I ever spent because it made me look like I knew what I was doing and I have zero liability to boot!

 

[stookeyfpe]

SD2:

To be the smartest guy in school purchase some of these:

http://www.dataq.com/usb-data-logge...vifTjADT8G_H_pLQZ6lwg.1&utm_referrer=https://

http://www.google.com/

http://www.microdaq.com/data-logger/temperature/1.php

I used these along with a legal affadavit against a major appliance manufacturer when I purchased a refrigerator 3 years ago. At the end of the days the legal fees made me lose $200 bucks but I got a refund, purchased a new refrigerator from a manufacturer who had a decent warranty. I slept better because the appliance manufacturer probably lost no money but I was able to help de-rate them in Consumer Reports.

For a few extra bucks the NIST calibration certificate confirms credability. It means they have a chain of custody for calibrations.

 

[chicopee]

There is no reason why you can not reason with the AHJ. If the AHJ insist then I would contact the State Fire Marshal to debunk the AHJ in writing. Also get a copy of the State codes regarding sprinkler protection in such structure for a way out of this AJH requirement.