B31.8 Contradiction: Class 1, Div 2 Test Pressure

[akoester]

Please let me know if I am missing something, but I am seeing a contradiction in the ASME B31.8-2010 spec in regards to required test pressure of Class 1, Div 2 pipeline.

Section 840.2.2(a)(2)
Class 1, Division 2. This Division is a Location Class 1 wherer the design factor of the pipe is equal to or less than 0.72 and has been tested to 1.1 times the maximum operating pressure.

Table 841.3.2-1 "Test Requirements for Steel Pipelnes and Mains to Operate at Hoop Stress of 30% or More of SMYS" then states that the Minimum Pressure Test Prescribed is 1.25 x MOP.

So 1.1x or 1.25x for Class 1, Div 2???

 

[BigInch]

840.2.2 (a) (2)

(2) Class 1, Division 2. This Division is a Location
Class 1 where the design factor of the pipe is equal to
or less than 0.72 and has been tested to 1.1 times the
maximum operating pressure. (See Table 841.1.6-2 for
exceptions to design factor.)

Class 1 areas where DF < 0.72 would normally only apply to,
Unimproved public roads
Roads, highways, or public streets, with hard surface and railroads
Fabricated assemblies
Pipelines on bridges
Pressure/flow control and metering facilities
Compressor station piping

The clause allows those areas to be included in Class 1 Division 2, even though they may have only been tested to 1.1 times the MOP.

Conversely it also appears to say that, if they were actually tested to 1.25 MOP, then they could be rated, or re-rated, up to an MOP as high as 1.25/1.1 = 1.136 DP.

I agree that it doesn't seem to make sense. Is it effectively a means to requalify existing C1 systems to a higher operating pressure. It appears to be so.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[BigInch]

I thought that I remembered the 2007 code actually had provisions for testing at 1.1 MOP so I checked that code edition.
Sure enough, in the 841.322(f) table the 1.1 factor appears. I have attached a picture of that table.

I have also found this at the ASME B31.8 committee webpage.

12-1136 B31.8 - Correction to Minimum Hydrostatic Test Pressures ------ Out for Stds Comm Blt

There is no further information posted there for public consumption, so I have no way of knowing for sure, but it appears that this apparent discrepancy may be in the process of correction. I would suppose that it will be updated to 1.25



"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek