DESIGN CRITERIA FOR VALVE STUFFING BOXES?

[Bambie]

Does anyone know how to determine the maximum design pressure criteria for valve stuffing boxes and what factor of safety is available for packing compression?

 

[LittleInch]

Whatever the valve design pressure / pressure rating is.

Factor of safety over what? Stuffing glands leak - but this isn't a safety issue normally

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Bambie]

LittleInch,

Most packing material needs several thousand psi to seal the stem regardless the valve body pressure rating.

Stem seizure and stuffing box rupture might become a safety issue.

The reason I ask is that gland follower studs are not low strength like you might expect, similar to cast iron flange requirements in B31.1 Table 112, yet they can generate tens of thousands of psi in the stuffing box.