svi
Mechanical
- Aug 1, 2006
- 142
What seems to be the intend of the hydro test specified through the below, Is it not a strength test. At 2500 psi, it does not seem to be.
"22. Hydrostatic Test Requirements
22.1 Except as provided in 22.2 and 22.3, each length of
pipe shall be tested by the manufacturer to a hydrostatic
pressure which will produce in the pipe wall a stress not less
that 60 % of the minimum specified yield strength for carbon
and ferritic alloy steel pipe, or 50 % of the specified minimum
yield strength for austenitic alloy steel pipe. The test pressure
or stress shall be determined by the following equation:
P 5 2St/D or S 5 PD/2t (3)
where:
P = hydrostatic test pressure in psi or MPa,
S = pipe wall stress in psi or MPa,
t = specified nominal wall thickness, nominal wall thickness
corresponding to specified ANSI schedule number,
or 1.143 times the specified minimal wall thickness,
in. [mm], and
D = specified outside diameter, outside diameter corresponding
to specified ANSI pipe size, or outside
diameter calculated by adding 2t (as defined above) to
the specified inside diameter, in. [mm].
22.1.1 The hydrostatic test pressure determined by the
equation shall be rounded to the nearest 50 psi [0.5 MPa] for
pressures below 1000 psi [7 MPa], and to the nearest 100 psi
[1 MPa] for pressures 1000 psi [7 MPa] and above. The
hydrostatic test may be performed prior to cutting to final
length, or prior to upsetting, swaging, expanding, bending, or
other forming operations.
22.2 Regardless of pipe-wall stress-level determined by Eq
3, the minimum hydrostatic test pressure required to satisfy
these requirements need not exceed 2500 psi [17.0 MPa] for
outside diameters (see D in 22.1) of 3.5 in. [88.9 mm] or less,
nor 2800 psi [19.0 MPa] for outside diameters over 3.5 in.
[88.9 mm]. This does not prohibit testing at higher pressures at
the manufacturer’s option or as provided in 22.3.
22.3 With concurrence of the manufacturer, a minimum
hydrostatic test pressure in excess of the requirements of 22.2
or 22.1, or both, may be stated on the order.
22.4 The test pressure shall be held for a minimum of 5 s,
without resultant leakage through the pipe wall. For welded
pipe, the test pressure shall be held for a time sufficient to
permit the inspector to examine the entire length of the welded
seam."
"22. Hydrostatic Test Requirements
22.1 Except as provided in 22.2 and 22.3, each length of
pipe shall be tested by the manufacturer to a hydrostatic
pressure which will produce in the pipe wall a stress not less
that 60 % of the minimum specified yield strength for carbon
and ferritic alloy steel pipe, or 50 % of the specified minimum
yield strength for austenitic alloy steel pipe. The test pressure
or stress shall be determined by the following equation:
P 5 2St/D or S 5 PD/2t (3)
where:
P = hydrostatic test pressure in psi or MPa,
S = pipe wall stress in psi or MPa,
t = specified nominal wall thickness, nominal wall thickness
corresponding to specified ANSI schedule number,
or 1.143 times the specified minimal wall thickness,
in. [mm], and
D = specified outside diameter, outside diameter corresponding
to specified ANSI pipe size, or outside
diameter calculated by adding 2t (as defined above) to
the specified inside diameter, in. [mm].
22.1.1 The hydrostatic test pressure determined by the
equation shall be rounded to the nearest 50 psi [0.5 MPa] for
pressures below 1000 psi [7 MPa], and to the nearest 100 psi
[1 MPa] for pressures 1000 psi [7 MPa] and above. The
hydrostatic test may be performed prior to cutting to final
length, or prior to upsetting, swaging, expanding, bending, or
other forming operations.
22.2 Regardless of pipe-wall stress-level determined by Eq
3, the minimum hydrostatic test pressure required to satisfy
these requirements need not exceed 2500 psi [17.0 MPa] for
outside diameters (see D in 22.1) of 3.5 in. [88.9 mm] or less,
nor 2800 psi [19.0 MPa] for outside diameters over 3.5 in.
[88.9 mm]. This does not prohibit testing at higher pressures at
the manufacturer’s option or as provided in 22.3.
22.3 With concurrence of the manufacturer, a minimum
hydrostatic test pressure in excess of the requirements of 22.2
or 22.1, or both, may be stated on the order.
22.4 The test pressure shall be held for a minimum of 5 s,
without resultant leakage through the pipe wall. For welded
pipe, the test pressure shall be held for a time sufficient to
permit the inspector to examine the entire length of the welded
seam."