Gentlemen - I am looking for an interpretation of B31.3 testing
requirements. The system in question is a natural gas process piping
system located on & connecting 2 offshore platforms, 1440# MAWP @ ambient
temperature, 24" / 30" dia. with approx. 500 lin. feet. At one end of the
system we need to flip an existing 30"-600#rf spec blind from the closed
position to the open position, at the other extreme end we are installing
a new 24"-600# double block & bleed isolation valve to an existing 24"600#
RF Flg. as part of a phase 2 construction project. Unfortunately during
original piping installation high point vents & low point drains were not
installed - ruling out hydrotesting.."Hot Work" is not allowable.
Please help me with the following:
1) 345.2.3 Special Provisions for Testing
(b) Flanged Joints. A flanged joint at which a blank is inserted to
isolate other equipment during a test need not be tested.
Does "Equipment" include piping systems as well? Will simple rotating of a
Spec Blind require code testing?
2) 345.3.4 Limits of Tested Piping.
Equipment which is not to be tested shall be either disconnected
from the piping or isolated by blinds or other means during the test. A
valve may be used provided the valve (including its closure mechanism) is
suitable for the test pressure.
Does "Equipment" include piping systems as well? Will the flanged joint
between the existing flange & new valve qualify under 345.2.3?
3) 345.1 Required Leak Test
(c) Where the owner considers both hydrostatic and pneumatic leak testing impracticable, the alternative specified in para. 345.9 may be used if both of the following conditions apply:
(1) a hydrostatic test would damage linings or internal insulation, or contaminate a process which would be hazardous, corrosive, or inoperative in the presence of moisture, or would present the danger of brittle fracture due to low metal temperature during the test; and Hydrotest not possible due to lack of H.P. Vents & L.P. Drains. Moisture contamination not acceptable to treated NG.
(2) a pneumatic test would present an undue hazard of possible
release of energy stored in the system, or would present the danger of
brittle fracture due to low metal temperature during the test.
500 L.F. 24" / 30" @ 1580# test (I have a Bechtel chart which indicates a
maximum of 164 equivalent lineal feet for 24" 60S pipe @ 1600# to maintain
system within Stored Energy Limits)
4) 345.9 Alternative Leak Test
The following procedures and leak test method may be used only under the conditions stated in para. 345.1(c).
345.9.3 Test Method. The system shall be subjected to a sensitive leak test in accordance with para. 345.8. 5) 345.8 Sensitive Leak Test
The test shall be in accordance with the Gas and Bubble Test method specified in the BPV Code, Section V, Article 10, or by another method demonstrated to have equal sensitivity. Sensitivity of the test shall be not less than 10-3 atmˇml/sec under test conditions.
(a) The test pressure shall be at least the lesser of 105 kPa (15
psi) gage, or 25% or the design pressure.
(b) The pressure shall be gradually increased until a gage pressure
the lesser of one-half the test pressure or 170 kPa (25 psi) is attained,
at which time a preliminary check shall be made. Then the pressure shall
be gradually increased in steps until the test pressure is reached, the
pressure being held long enough at each step to equalize piping strains.
Are sections 345.9 & 345.8 applicable?
As always your valuable input is greatly appreciated -
Bruce R. Raymond
Fluor
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[Non-text portions of this message have been removed] Received on Thu Sep 27 10:18:00 2007
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