This ratio is the unsupported length of the extension stem, divided by the “radius of gyration” of the stem cross section. The unsupported length is the distance between the extension stem Operating Nut and the Bottom Coupling, or when stem guides are used, the longest distance between any two “supports.” It is typically used to determine the susceptibility of a column to buckling.
Zinc Anode Caps
Zinc Anode Caps are threaded end caps, shaped like hex nuts, which are fastened to the ends of bolts or studs on a buried pipeline or related pipeline component. The zinc in an Anode Cap sacrificially corrodes before the steel of the fasteners, fittings or related components, which helps protect these items, thus extending their life and preventing possible damage from failed fasteners.
Meaning of H-20
The American Association of State Highway and Transportation Officials developed a standard, M306 that calls for proof load testing for iron castings. For an H-20 proof load test, that standard requires a 40,000 lb. load be applied to a 9” x 9” square plate for one minute. Any cracks or permanent deformation greater than 1/8” are cause for rejection.
What is “Lead Free?”
As of January 4, 2014, the Reduction of Lead in Drinking Water Act (RLDWA) changed the allowable lead free content definition in Section 1417 of the Safe Drinking Water Act (SDWA) to a weighted average of not more than 0.25 percent lead, with respect to the wetted surfaces of pipes, fittings, valves and other fixtures. These are Federal regulations.