1. Roof Drains
Really!!

2. What has happened to the roof drain
30 years ago roof drains were rarely replaced at reroof time
Today it has become a common occurrence
Why?

3. What makes a good roof drain
Durability
Low height of free area in assembled drain
1 ½” drain bolts
Integral gravel stop
No plastic
Sump twice pipe diameter

4. What makes a good installation
Drain being installed at correct elevation
What is that elevation?
Roof insulation minus height of free area drainage
Overflow installed so as to allow primary system to reach it’s designed capacity.

5. ponding

6. Wrong Right

7. Drain Elevation

8. ASPE/IAPMO Flow test criteria Standardization of test rig
IPC is adopting the test criteria in to the 2015 code.
All manufacturers will be required to provide test results

9. DRAIN WITHOUT DRAIN PIPE
Water head (inch)
1"
2"
3"
4"
5"
6"
Flow of water into box (gpm)
118
202
402
616
714
870
Velocity of flow (ft/s)
1.8
4.5
6.2
7.8
3.3
3.2
DRAIN WITH 10 FT PIPE
120
192
397
604
704
866
Velocity in drain pipe (ft/s)
2.4
8.2
8.8
8.9
8.6
Pressure in drain pipe (in. W.C)
7.4
7.6
6.9
5.5
5.3
5.6
DRAIN WITH MODIFIED PIPES
117
210
401
596
916
1164
Velocity in 1st stack (ft/s)
2.9
4.2
5.0
7.0
Velocity in horizontal pipe (ft/s)
0.5
5.2
6.5
7.3
Velocity in 2nd stack (ft/s)
5.9
6.4
8.0
7.9
Pressure in 1st stack (in. W.C)
15.5
17.6
17.3
18.1
14.2
-5.4
Pressure in horizontal pipe (in. W.C)
-13.2
-13.3
-13.8
-11.7
-10.6
Pressure in 2nd stack (in. W.C)
6.0
1.9
-11.0
-22.4
-34.3
Flow
Water Head
gpm
Inch-W.C
100
1.8
200
2.7
300
5.2
400
N/A
500
600
Flow
Water Head
Pipe Press.
Velocity
gpm
Inch-W.C
inch-W.C
ft/s
100
1.9
2.1
3.1
200
2.3
1.2
3.5
300
3.4
-5.2
4.1
400
4.0
-12.5
4.3
500
4.4
-20.7
5.1
600
4.7
-25.8
5.6
700
4.9
-28.6
5.8
800
-36.8
6.3
900
5.2
-45.2
6.7
1000
N/A

11. ASME A112.6.4 is in revision Bringing larger sizes in to standard
Roof drain with integral overflow is being added
Suggestion was made to remove thickness requirements from the standard.

12. Green roof

13. Green Roof issues
What is the proper way to install a drain into a green roof, well that depends on the green roof
How do you make sure it will always drain
Are the new drain configurations safe?
Have they been flow tested?
How will maintenance be performed?

14. Only 20 minutes under perfect conditions

15. Drainage must be unobstructed

16. Siphonic Drains
Is a great idea and works, but what happens after it is installed?
Does anything in a building stay the same for the life of the building
What about building code variances
It gets disassembled and reassembled four to five times at least throughout the life of the building.
But by who?

17. The Roofer!!!