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Old School,,, Pipe Schedule system
- Thread starter cdafd
- Start date
TravisMack
Mechanical
Is the building small enough to allow for using pipe schedule method?
Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC
Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC
- Thread starter
- #3
SprinklerDesigner2
Mechanical
Did my first sprinkler drawing using the 1972 NFPA #13 edition when nearly everything, 90% at least, was still pipe schedule. Yeah, I am older than dirt.
When done correctly there were still hydraulics involved and they are involved today.
Let's assume an OH system using the 2019 edition of NFPA #13.
TABLE 19.3.2.1 Water Supply Requirements for Pipe Schedule Sprinkler Systems
Acceptable Flow at Base of Riser (Including Hose Stream Allowance) was 850 gpm to 1,500 gpm at base of riser.
The highest sprinkler was 24'-0" high.
Minimum pressure at the highest head was 15 psi.
The minimum pressure we had to have was (24*0.433)+15=25.4 gpm at the base of the riser.
If the system did not have an alarm we had to have 1,500 gpm at the base of the riser but if the system had a monitored alarm all we needed was 850 gpm. Assume we had a monitored alarm and 250' of 6" underground main from the base of the riser to the connection to the city water main. We had to calculate the head loss flowing 850 gpm through Class 52 cement lined DI pipe which was 4.5 psi.
At the base of the riser we had to have 850 gpm @ 29.9 psi.
Hydraulic calculations were coming on strong and in 1975 I attended a three day seminar presented by Jack Woods up at Viking's plant in Hastings, Michigan.
I started my career in Ohio and back then nobody but the insurance carrier (ISO, FM or IRI) ever wanted to see any sprinkler drawings and if we didn't have the water they could waive anything they wanted. Their attitude was "anything is better than nothing".
We called NFPA #13 the "Little Red Pamphlet" and you could literally fold it in half and carry it in your back pocket.
This is all from memory so I could be a little off... but to answer your question we had lots of systems with domestic coming off the riser inside the building which we never worried about.
When done correctly there were still hydraulics involved and they are involved today.
Let's assume an OH system using the 2019 edition of NFPA #13.
TABLE 19.3.2.1 Water Supply Requirements for Pipe Schedule Sprinkler Systems
Acceptable Flow at Base of Riser (Including Hose Stream Allowance) was 850 gpm to 1,500 gpm at base of riser.
The highest sprinkler was 24'-0" high.
Minimum pressure at the highest head was 15 psi.
The minimum pressure we had to have was (24*0.433)+15=25.4 gpm at the base of the riser.
If the system did not have an alarm we had to have 1,500 gpm at the base of the riser but if the system had a monitored alarm all we needed was 850 gpm. Assume we had a monitored alarm and 250' of 6" underground main from the base of the riser to the connection to the city water main. We had to calculate the head loss flowing 850 gpm through Class 52 cement lined DI pipe which was 4.5 psi.
At the base of the riser we had to have 850 gpm @ 29.9 psi.
Hydraulic calculations were coming on strong and in 1975 I attended a three day seminar presented by Jack Woods up at Viking's plant in Hastings, Michigan.
I started my career in Ohio and back then nobody but the insurance carrier (ISO, FM or IRI) ever wanted to see any sprinkler drawings and if we didn't have the water they could waive anything they wanted. Their attitude was "anything is better than nothing".
We called NFPA #13 the "Little Red Pamphlet" and you could literally fold it in half and carry it in your back pocket.
This is all from memory so I could be a little off... but to answer your question we had lots of systems with domestic coming off the riser inside the building which we never worried about.
stookeyfpe
Specifier/Regulator
If your adopted fire code is the 2015 IFC or an older edition the arrangement is prohibited because of the design method. See Limited Area Sprinkler Systems in Section 903.3.8. This design is limited to 6 sprinklers, Light or Ordinary Hazard Group 1 occupancy hazard classifications and must be calculated to confirm the system can meet the required water flow and pressure within the fire area being protected by the Limited Area sprinkler provisions.
- Thread starter
- #6
Scott,
But straight NFPA 13 seems to allow it.
Pipe schedule can be used on new systems, in some settings
2016 edition
11.2.2.3
And appears you can have combined domestic and sprinkler
24.1.3.3
24.1.4
Just trying to see if possible per NFPA 13
But straight NFPA 13 seems to allow it.
Pipe schedule can be used on new systems, in some settings
2016 edition
11.2.2.3
And appears you can have combined domestic and sprinkler
24.1.3.3
24.1.4
Just trying to see if possible per NFPA 13
stookeyfpe
Specifier/Regulator
It still may be allowed if your jurisdiction hasn't adopted the 2015 or later edition of the IFC. Chapter 1 of the IFC states that when their is a difference between the IFC and a standard, the IFC governs.
- Thread starter
- #8
Scott I concur that IFC comes first.
This would not be a limited area sprinkler system.
It is about a 1800 sq ft B occupancy.
Going to be gutted inside.
Building is already sprinkled, in the 80’s.
Appears to be pipe schedule.
Just trying to see if legal per NFPA 13 to do a pipe schedule
This would not be a limited area sprinkler system.
It is about a 1800 sq ft B occupancy.
Going to be gutted inside.
Building is already sprinkled, in the 80’s.
Appears to be pipe schedule.
Just trying to see if legal per NFPA 13 to do a pipe schedule
stookeyfpe
Specifier/Regulator
I didn't understand what you were trying to do. Your original post implied you were attempting to supply an automatic sprinkler system using a domestic water supply.
- Thread starter
- #10
Sorry
There is an existing 2 1/2 inch line
I think it currently feeds both the fire sprinkler system and domestic service for the building.
If legal per 13 seeing if this is still an option.
1. If they can properly separate the domestic and fire.
2. If they have enough pressure to do a pipe schedule.
No flow or pressure data yet.
Thank you for your help
There is an existing 2 1/2 inch line
I think it currently feeds both the fire sprinkler system and domestic service for the building.
If legal per 13 seeing if this is still an option.
1. If they can properly separate the domestic and fire.
2. If they have enough pressure to do a pipe schedule.
No flow or pressure data yet.
Thank you for your help
SprinklerDesigner2
Mechanical
Putting the IFC aside for a moment it seems to me that if you have enough to supply a pipe schedule system you should certainly be able to design a fully compliant calculated system and be done with it.
Looking at my 1980 edition of NFPA #13 Table 2-2.1(A) required a minimum residual pressure of 15 psi for Light and OH I and OH II pipe schedule systems.
The pressure required at the base of the riser was defined as 15 psi at the highest sprinkler plus the elevation to reach it. If the head was 12'-0" you needed a minimum pressure of (0.433*12)+15.0=20.2 psi at the base of the riser.
That being said TABLE 19.3.2.1 in the 2019 edition calls for 15 psi for Light Hazard and 20 psi for OH systems.
That being said the kicker was we had to have 500 to 750 gpm at the base of the riser with 500 gpm acceptable but note #3 stated 250 gpm was acceptable if the building was compartmented and the building was non-combustible construction.
Under the best of conditions we had to have 250 gpm @ 20.2 psi for for Light Hazard systems under the best of conditions.
Unless a killer backflow has been added I would have to think one could design a hydraulically calculated system if you have the required 250 gpm @ 20.2 psi at the base of the riser.
The smallest ductile or cast iron pipe I have seen was 3" but if you have 2 1/2" using a C-Value of 120 you will lose 20.3 psi through 100' equivalent feet of 2 1/2" pipe from the base of the riser to the point of connection.
For a light hazard system you will need a minimum of 20.3+20.2=40.5 psi at the street to make the pipe schedule system compliant to the 1980 standard.
Assuming a height of 12' with a reduced QR area to 1,000 sq ft for a light hazard occupancy you might need 150 gpm at the high side which should be easily doable if you can do the pipe schedule system. I am willing to bet a pipe schedule system would even be costlier.
Looking at my 1980 edition of NFPA #13 Table 2-2.1(A) required a minimum residual pressure of 15 psi for Light and OH I and OH II pipe schedule systems.
The pressure required at the base of the riser was defined as 15 psi at the highest sprinkler plus the elevation to reach it. If the head was 12'-0" you needed a minimum pressure of (0.433*12)+15.0=20.2 psi at the base of the riser.
That being said TABLE 19.3.2.1 in the 2019 edition calls for 15 psi for Light Hazard and 20 psi for OH systems.
That being said the kicker was we had to have 500 to 750 gpm at the base of the riser with 500 gpm acceptable but note #3 stated 250 gpm was acceptable if the building was compartmented and the building was non-combustible construction.
Under the best of conditions we had to have 250 gpm @ 20.2 psi for for Light Hazard systems under the best of conditions.
Unless a killer backflow has been added I would have to think one could design a hydraulically calculated system if you have the required 250 gpm @ 20.2 psi at the base of the riser.
The smallest ductile or cast iron pipe I have seen was 3" but if you have 2 1/2" using a C-Value of 120 you will lose 20.3 psi through 100' equivalent feet of 2 1/2" pipe from the base of the riser to the point of connection.
For a light hazard system you will need a minimum of 20.3+20.2=40.5 psi at the street to make the pipe schedule system compliant to the 1980 standard.
Assuming a height of 12' with a reduced QR area to 1,000 sq ft for a light hazard occupancy you might need 150 gpm at the high side which should be easily doable if you can do the pipe schedule system. I am willing to bet a pipe schedule system would even be costlier.
- Thread starter
- #12
SD2
Thank you for that analysis.
There is possibly 340 existing 2 1/2 cooper service
I think it serves both domestic a fire sprinkler.
For reasons, trying to see if it could still be used, via pipe schedule
Thoughts on doing hydraulic calc??
I just did not know if hydraulic calc, about the cooper underground
Thank you
Thank you for that analysis.
There is possibly 340 existing 2 1/2 cooper service
I think it serves both domestic a fire sprinkler.
For reasons, trying to see if it could still be used, via pipe schedule
Thoughts on doing hydraulic calc??
I just did not know if hydraulic calc, about the cooper underground
Thank you
SprinklerDesigner2
Mechanical
In my opinion a hydraulically calculated system is the only way you have any chance of making the 2 1/2" underground work.
The size of the building and the fact that the domestic water comes off the same 2 1/2" line is irrelevant. If your ceiling is 12' high the area of application with quick response sprinklers will be 945 sq ft.
The theoretical minimum amount of water the system will need is 95.5 gpm for Light Hazard and that doesn't change if the building is 1,000 sq ft or 50,000 sq ft the theoretical minimum amount of water you will need remains at 95.5 gpm.
Just the way it normally works we all know the actual amount of water you will need is around 110 to 125 gpm but we will work on that in a bit.
For above ground pipe we will use Sch. 40 and for the underground let's use Type M copper with an ID of 2.495"
Experience tells me you will need a double detector check so let's use an Ames Colt [URL unfurl="true"]https://www.vikinggroupinc.com/sites/default/files/documents/ES-A-C200-C200N.pdf[/url]
Use Group B I am assuming it is an office or what? If it is an office the density will be .10 gpm but if a small mercantile shop it would be Ord Haz II with will be a density of .20 gpm over the 945 sq ft.
If Light Hazard space your K5.6 heads as close to 148 sq ft as possible so we achieve the 7.0 psi end head pressure. If Ord Haz use K8.0 heads spacing them as close to 106 sq ft as possible again to achieve the 7.0 psi end head pressure.
If spaced right for Light Hazard we will calculate 7 pendent sprinklers on 1" drops but now is not the time to scrimp on pipe size.. my branch lines will all be 2" with a 2 1/2" feed main. At 120 gpm I would estimate the total friction loss of the overhead system to be less than 6.0 psi but let's call it 8.0 psi to be on the safe side.
At the base of the riser we can expect to need 7.0 psi end head pressure plus 8.0 psi friction loss plus 12*.433=5.2 psi elevation for a total head requirement of 20.2 psi flowing 120 gpm.
At the backflow we can expect another head loss of 5.8 psi bringing us to a total of 26.0 psi at the base of the riser with the backflow assembly.
For the underground we have 340' of Type M copper and to this I added 40 equivalent feet of fittings just to be on the safe side for a total of 380 equivalent feet. Flowing 120 gpm our head loss through the underground is 0.035 psi/ft and we end up with an underground loss of 13.24 psi. At the street you will need 20.2+13.3=33.5 psi @ 220 gpm (I added the 100 gpm hose stream at the city connection). For Light Hazard this is easily doable with most city water supplies that I have seen.
In my opinion the only way to do this is by installing a hydraulically designed system... forget the pipe schedule.
If a shop we would be Ordinary Hazard Group II and we could run into difficulty.
Most likely you will have heads spaced as close to 106 sq ft as possible and we are going to calculate 10 heads. Overhead pipe will be 2" branch lines with 2 1/2" cross mains with cross mains looped if need be. The cost of the overhead system is negligible when compared to having to replace the underground with a 4" main so we will do whatever we have to design a system with the lowest possible pressure requirement.
With 10 heads flowing 21.2 gpm we will need around 220 gpm if we do it right.
At the base of the riser we can expect to need 7.0 psi end head pressure plus 10.0 psi friction loss plus 12*.433=5.2 psi elevation for a total head requirement of 22.2 psi flowing 220 gpm.
Head loss through the backflow will be about 6.0 psi bringing us to 220 gpm @ 28.2 psi at the base of the riser.
Our head loss through the 380 equivalent feet of 2 1/2" underground is 40.6 psi bringing us to a required supply of 470 gpm @ 68.8 psi which would be a problem in more than half the country (guess on my part) so I hope your building is an office and not a mercantile store.
I assumed a ceiling height of 12'-0" but if it is lower it would be to our advantage by maybe one pound. I assumed Type M copper but if Type K or Type L it would be to our advantage and, with that said, my guess is that it is Type L.
The size of the building and the fact that the domestic water comes off the same 2 1/2" line is irrelevant. If your ceiling is 12' high the area of application with quick response sprinklers will be 945 sq ft.
The theoretical minimum amount of water the system will need is 95.5 gpm for Light Hazard and that doesn't change if the building is 1,000 sq ft or 50,000 sq ft the theoretical minimum amount of water you will need remains at 95.5 gpm.
Just the way it normally works we all know the actual amount of water you will need is around 110 to 125 gpm but we will work on that in a bit.
For above ground pipe we will use Sch. 40 and for the underground let's use Type M copper with an ID of 2.495"
Experience tells me you will need a double detector check so let's use an Ames Colt [URL unfurl="true"]https://www.vikinggroupinc.com/sites/default/files/documents/ES-A-C200-C200N.pdf[/url]
Use Group B I am assuming it is an office or what? If it is an office the density will be .10 gpm but if a small mercantile shop it would be Ord Haz II with will be a density of .20 gpm over the 945 sq ft.
If Light Hazard space your K5.6 heads as close to 148 sq ft as possible so we achieve the 7.0 psi end head pressure. If Ord Haz use K8.0 heads spacing them as close to 106 sq ft as possible again to achieve the 7.0 psi end head pressure.
If spaced right for Light Hazard we will calculate 7 pendent sprinklers on 1" drops but now is not the time to scrimp on pipe size.. my branch lines will all be 2" with a 2 1/2" feed main. At 120 gpm I would estimate the total friction loss of the overhead system to be less than 6.0 psi but let's call it 8.0 psi to be on the safe side.
At the base of the riser we can expect to need 7.0 psi end head pressure plus 8.0 psi friction loss plus 12*.433=5.2 psi elevation for a total head requirement of 20.2 psi flowing 120 gpm.
At the backflow we can expect another head loss of 5.8 psi bringing us to a total of 26.0 psi at the base of the riser with the backflow assembly.
For the underground we have 340' of Type M copper and to this I added 40 equivalent feet of fittings just to be on the safe side for a total of 380 equivalent feet. Flowing 120 gpm our head loss through the underground is 0.035 psi/ft and we end up with an underground loss of 13.24 psi. At the street you will need 20.2+13.3=33.5 psi @ 220 gpm (I added the 100 gpm hose stream at the city connection). For Light Hazard this is easily doable with most city water supplies that I have seen.
In my opinion the only way to do this is by installing a hydraulically designed system... forget the pipe schedule.
If a shop we would be Ordinary Hazard Group II and we could run into difficulty.
Most likely you will have heads spaced as close to 106 sq ft as possible and we are going to calculate 10 heads. Overhead pipe will be 2" branch lines with 2 1/2" cross mains with cross mains looped if need be. The cost of the overhead system is negligible when compared to having to replace the underground with a 4" main so we will do whatever we have to design a system with the lowest possible pressure requirement.
With 10 heads flowing 21.2 gpm we will need around 220 gpm if we do it right.
At the base of the riser we can expect to need 7.0 psi end head pressure plus 10.0 psi friction loss plus 12*.433=5.2 psi elevation for a total head requirement of 22.2 psi flowing 220 gpm.
Head loss through the backflow will be about 6.0 psi bringing us to 220 gpm @ 28.2 psi at the base of the riser.
Our head loss through the 380 equivalent feet of 2 1/2" underground is 40.6 psi bringing us to a required supply of 470 gpm @ 68.8 psi which would be a problem in more than half the country (guess on my part) so I hope your building is an office and not a mercantile store.
I assumed a ceiling height of 12'-0" but if it is lower it would be to our advantage by maybe one pound. I assumed Type M copper but if Type K or Type L it would be to our advantage and, with that said, my guess is that it is Type L.
- Thread starter
- #14
TravisMack
Mechanical
One minor caveat and I am going from memory, so it may not be 100% accurate. When the supply is <4" and serving both domestic and fire, you have to include the domestic demand with your sprinkler demand through the underground. That could be a problem with the 2½" supply.
Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC
Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC
- Thread starter
- #16
SprinklerDesigner2
Mechanical
Where's that found?
Must be a building or fire code I don't know about?
Must be a building or fire code I don't know about?
- Thread starter
- #18
NFPA 13 2016
24.1.3.3
Where a single main less than 4 in. (100 mm) in diameter serves both fire systems and other uses, the non-fire demand shall be added to the hydraulic calculations for the fire system at the point of connection unless provisions have been made to automatically isolate the non-fire demand during a fire event.
Simultaneous flow of the non-fire water and automatic sprinkler systems must be considered when small diameter [i.e., less than 4 in. (100 mm)] combination lead-ins are used. The additional non-fire waterflow can create increased friction loss resulting in a reduction in the water available for the sprinkler system.
24.1.4 Underground Supply Pipe.
For pipe schedule systems, the underground supply pipe shall be at least as large as the system riser.
The requirements of 24.1.4 apply regardless of the type of water supply used.
HISTORICAL NOTE
For the 2013 edition, the term domestic was replaced with non-fire. This change was made to emphasize that any water that is flowing needs to be accounted for whether it was being used for domestic use or other uses.
24.1.3.3
Where a single main less than 4 in. (100 mm) in diameter serves both fire systems and other uses, the non-fire demand shall be added to the hydraulic calculations for the fire system at the point of connection unless provisions have been made to automatically isolate the non-fire demand during a fire event.
Simultaneous flow of the non-fire water and automatic sprinkler systems must be considered when small diameter [i.e., less than 4 in. (100 mm)] combination lead-ins are used. The additional non-fire waterflow can create increased friction loss resulting in a reduction in the water available for the sprinkler system.
24.1.4 Underground Supply Pipe.
For pipe schedule systems, the underground supply pipe shall be at least as large as the system riser.
The requirements of 24.1.4 apply regardless of the type of water supply used.
HISTORICAL NOTE
For the 2013 edition, the term domestic was replaced with non-fire. This change was made to emphasize that any water that is flowing needs to be accounted for whether it was being used for domestic use or other uses.
SprinklerDesigner2
Mechanical
Learn something new every day!
Georgia just moved from the 2013 edition to 2019 and I am still reading the handbook trying to catch up.
Georgia just moved from the 2013 edition to 2019 and I am still reading the handbook trying to catch up.
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