ISA RP3.1 PDF

It is not intended to set rigid specifications for materials, fabrication,l pressure rating, and similar points since these should ordinarily be in compliance with code requirements which are established for the particular industry concerned.

It is recognized that a wide variety of special forms of chambers, dimensions and operating principles have been recommend by instrument manufacturers, and have been successfully used throughout the measurement field. The forms advocated by this report, however, are consistent with those available either from manufacturers or by field fabrication, and are currently used in a great number of installations. Various more elaborate forms of seal and condensate chamber offer operational advantages, but are difficult to field-fabricate therefore not considered to be within the scope of this report.

PURPOSE

Head-type fluid meter installations will be simplified considerably by the adoption of uniform practices in the fabrication of their seal and condensate chambers. This uniformity pertains to the over-all dimensions, general arrangement and location of connections, and minimum sealing volume required by conventional meters. Pursuant to the adoption of the recommendations contained in this report, all similar types of seal and condensate chambers would be interchangeable with respect to installation dimensions, regardless of their source of supply.