LABORATORY TEST REPORT
FOR ULTIMATE LOAD OF SET SCREWS ON PIPE


Clamp
Size
Ref.
Nom.
Pipe
Size
No. of
Setscrews
Torque
(ft.lbs.)
Ultimate
Load
(lbs.)
Results
5
3/4"
1
20
1500
Pipe Failure
6
1"
1
20
1600
Pipe Failure
7
1 1/4"
1
20
1750
Pipe Failure
8
1 1/2"
1
20
2200
Pipe Failure

Tests were carried out by an independent laboratory using the following method:
  • A single slip-on pipe tee clamp with one case hardened set screw.
  • Two pieces of Schedule 40 standard black pipe at 24" long.

One pipe was inserted into the vertical barrel of the clamp with the set screw tightened to 20 ft lbs torque, as shown in the above diagram. A Baldwin State Universal Testing Machine was used to pull the connections apart to determine the Ultimate Load Capacity. The above test results represent the Ultimate Load Capacity for each of the test conditions shown (no safety factors are included). At this point, for each of the listed tests conditions, failure occurred when the set screw would score the pipe, resulting in the pipe being pulled out of the clamp.

To determine pipe and clamp sizes to support a required load, please use the following method:

  1. Divide Ultimate Load Capacity by the appropriate safety factor.
  2. Check pipe Load Capacity Chart.
  3. Use the lower of the two results.