A question on pipe stands-installed per NFPA 13-2019 edition.
To support valve headers, components, valves, backflow preventers, I understand you need to support the load with a stand of 2" sch. 40 pipe, of a maximum length of 4 feet, as noted below:
188.8.131.52* Pipe diameters up to and including 10 in. (250 mm) Schedule 40 are permitted to be
supported by 2 in. (50 mm) diameter pipe stands when all of the following conditions are met:
(1) The maximum height shall be 4 ft (1.2 m), as measured from the base of the pipe stand to
the centerline of the pipe being supported.
(2)* The pipe stand shall be axially loaded.
Axial loading requires that the pipe or valve being supported be located directly above the pipe stand.
A.184.108.40.206 These short pipe stands commonly support items such as backflow preventers,
header piping, and other appurtenances.
The pipe or device is supported and secured to the 2" vertical support pipe by a riser clamp, channel or angle iron with a U bolt, etc.
My question-does the 2" vertical support pipe need to attach directly to the riser clamp or support (threaded coupling, welded,# etc.) , or is a threaded rod with adjustment nut acceptable per the standard, as shown in the example below? I'm confused-as I see a lot of stands like this in the marketplace, and to me a lot of weight could be bearing on that rod. If it is undersized-it could deflect and fail. Secondly-some designs have the rod and adjustment nut assembly set in the support pipe unsecured. A sudden thrust could move the assembly out of position.