Question about UG-99 (b) (c) and (g) Hydrotest
Question about UG-99 (b) (c) and (g) Hydrotest
(OP)
1. UG-99 (b) vs UG-99 (c)
I think in both cases we measure hydrotest pressure on top of equipment.In both of case liquid is full.
In case of UG-99 (b) Hydrotest pressure = 1.3 * MAWP * Stress ratio
Does UG-99 (C) Hydortest pressure = 1.3 * MAWP - Hydro static Head?
How should the hydro static head be calculated? As it is supposed to be 0 at the top of the equipment.
2. UG-99 (g)
This tells us the acceptable critia, but there is a sentence like "This inspection shall be made at a pressure not less than the test pressure divde by 1.3"
I am confused if the inspection is made when the test pressure on the vessel or after the test pressure is been released?
Thanks!
I think in both cases we measure hydrotest pressure on top of equipment.In both of case liquid is full.
In case of UG-99 (b) Hydrotest pressure = 1.3 * MAWP * Stress ratio
Does UG-99 (C) Hydortest pressure = 1.3 * MAWP - Hydro static Head?
How should the hydro static head be calculated? As it is supposed to be 0 at the top of the equipment.
2. UG-99 (g)
This tells us the acceptable critia, but there is a sentence like "This inspection shall be made at a pressure not less than the test pressure divde by 1.3"
I am confused if the inspection is made when the test pressure on the vessel or after the test pressure is been released?
Thanks!
3 years industry experience;
Oil & Gas industry in Canada.





RE: Question about UG-99 (b) (c) and (g) Hydrotest
UG-99(b) says that Hydrotest pressure = 1.3 * MAWP * Stress ratio, MAWP may be assumed to be same as design pressure, likewise which stamp on nameplate.
UG-99(c) says that Hydortest pressure = 1.3 * MAWP - Hydro static Head, MAWP is determined by calculated, general the MAWP > design pressure.
You may be select (b) or (c) to determine test pressure. but general condition, (b) is usual.
UG-99(g), when inspector does inspection,the pressure shall be down to a value which test preesure divid by 1.3.such as test pressure is 1.3Mpa, inspection pressure shall be 1.3/1.3=1Mpa after enough holding time.
RE: Question about UG-99 (b) (c) and (g) Hydrotest