# Roof Drain to column or beam



## sergoodo (Aug 25, 2016)

Other than being questionable, anything in the code restricting the use of the inside of structural pipe/tube for roof drainage?


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## steveray (Aug 25, 2016)

Not listed or approved "plumbing" pipe....1102 for storm sends you to 702 for "normal" indoor drainage pipe....You might be able to get a stainless or galvanized pipe to meet both needs, but I doubt it...


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## FLSTF01 (Aug 25, 2016)

I fully agree with the above.


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## BayPointArchitect (Aug 30, 2016)

After careful "analysis by those of us who apply our codes on a daily basis", it has been determined that a number of steel pipes would suffice.  Assuming that you are familiar with Schedule 40 pipe that is commonly used for plumbing (not galvanized or stainless steel or made of gold) I would like to introduce to you Schedule 80 pipe and Schedule 160 pipe.  The thinking is that the pipe will eventually deteriorate much like the Schedule 40 that is allowed by the plumbing code.  But a pipe with twice the wall thickness will stand strong twice as long.

Ask your structural engineer to consider an 8 inch diameter schedule 80 pipe with a wall thickness of 1/2".  If he still has reservations, apply a greater factor of safety and call out a schedule 160 pipe with a wall thickness of 0.905 inch.  Albeit it weighs 75 plf and you will need to detail how the water get routed out of the pipe just above the pad footing.

Let's be like architects and think outside the box today.  By the time that combination column/drain rusts through, our great-grandchildren will need to deal with it.


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## steveray (Aug 30, 2016)

Is the steel pipe you speak of referenced in Table 702.1?


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## BayPointArchitect (Aug 30, 2016)

INo, it is not listed among the pipes that are suitable for sewer waste.  If you look carefully at the standards associated with each of those pipes, they are expected to provide corrosion resistance against poop and pee.  But I thought we were talking about rain water here (acid rain?).  The standard associated with the steel pipe that I speak of will perform the same with regards to being suitable for steam, water, high-pressure gas/air.  The extra heavy pipe goes beyond the prescriptive solution and will be permissible only by plumbing inspectors who can think outside the box.  I refer to building officials whose heads are not pointy at the top.  I can give you the contact information of one plumbing inspector as an example.


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## mtlogcabin (Aug 30, 2016)

If it is just rain water then I agree galvanized steel pipe could be used. The question is with regards to how the water gets into the pipe and what is it supporting that you put a big hole in the wall of the pipe.

The structural engineer would need to be involved
Galvanized pipe would be required by code

1102.2 Inside storm drainage conductors.
Inside storm drainage conductors installed above ground shall conform to one of the standards listed in Table 702.1.

TABLE 702.1
ABOVE-GROUND DRAINAGE AND VENT PIPE


MATERIAL   STANDARD  
Acrylonitrile butadiene styrene    ASTM D 2661; ASTM F 628; ASTM F 1488; CSA B181.1   
   (ABS) plastic pipe in IPS diameters, including Schedule 40, DR 22 (PS 200) and DR 24 (PS 140); with a solid, cellular core or composite wall   
Brass pipe    ASTM B 43   
Cast-iron pipe    ASTM A 74; ASTM A 888; CISPI 301   
Copper or copper-alloy pipe    ASTM B 42; ASTM B 302   
Copper or copper-alloy tubing   ASTM B 75; ASTM B 88; ASTM B 251; ASTM B 306   
   (Type K, L, M or DWV)   
Galvanized steel pipe    ASTM A 53    
Glass pipe    ASTM C 1053   
Polyolefin pipe    ASTM F 1412;
CSA B181.3   
Polyvinyl chloride (PVC)   ASTM D 2665; ASTM F 891; ASTM F 1488; CSA B181.2   
   plastic pipe in IPS diameters, including schedule 40, DR 22 (PS 200), and DR 24 (PS 140); with a solid, cellular core or composite wall   
Polyvinyl chloride (PVC)   ASTM D 2949, ASTM F 1488   
   plastic pipe with a 3.25-inch O.D. and a solid, cellular core or composite wall  
Polyvinylidene fluoride
  (PVDF) plastic pipe    ASTM F 1673; CSA B181.3   
Stainless steel drainage
  systems, Types 304 and 316L    ASME A112.3.1


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## ADAguy (Aug 30, 2016)

Love it Chemistry and Physics, and if necessary you could always line or sleeve the interior of the pipe/tube with many corrosion resistant products out there. Nice response "Bay"


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## steveray (Aug 31, 2016)

An inspector that thinks outside the box here, is negligent and personally liable....You ever see a plain steel tube column exposed to weather?  Ohhhh....That's right....California doesn't have weather...
This is what they look like in 20 yrs WITHOUT water running through them...





And let me tell you about galvanized drainage pipe, few and far between are the ones I see that have not been halved in ID by rust over 30 yrs or so....


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## Paul Sweet (Aug 31, 2016)

It would be interesting to see how they propose to get the water out of the pipe.


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## my250r11 (Aug 31, 2016)

steveray said:


> And let me tell you about galvanized drainage pipe, few and far between are the ones I see that have not been halved in ID by rust over 30 yrs or so....



Galvanized on outside only


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