scope:

PURPOSE

This John C. Stennis Space Center (SSC) standard (SSTD) provides the design requirements and operating limits for tubing and tube fittings at Stennis Space Center for facility and special test equipment (STE). This standard may be used for aerospace hardware tubing systems where deemed appropriate. These provisions are intended to assure system reliability, safety, and cost effective interchangeability between tube system hardware and components.

APPLICABILITY

This standard covers all facility and STE tubing systems erected/assembled with the following:

a. Tubing with 37° flared ends

b. Tubing with flareless ends connected to Swagelok® type flareless tube fitting end connections 

c. Tubing with coned- and left hand-threaded ends

d. Tube fittings with 37° flared, Swagelok® type flareless, (American) National (Standard Taper) Pipe Thread (ANSI/ASME B1.20.1) (NPT), and coned- and left hand-threaded end connections

e. Fittings with Society of Automotive Engineers (SAE) (formerly AN/MS) straight internal (female) thread patterned boss connections

f. Fittings with SAE (formerly AN/MS) straight thread external (male) thread patterned end connections that connect to boss connections as stated in e., above.

Tube fittings that have end connections other than those listed above are not governed by and are not permitted under this standard.

Pressure and temperature ratings are specified for tubes with outside diameters between 0.250" (6.35 mm) and 2.00" (50.8 mm) with wall thicknesses of 0.028" (0.71 mm) and over. Other diameters and wall thicknesses may be used provided they meet the minimum requirements of ANSI/ASME B31.3.

Piping supplied per Nominal Pipe Size (NPS) (e.g., 8" Schedule 5S, 2" Schedule 40, etc.) is not governed by this standard. However, pipe that is threaded and connected to NPT fitting connections may reduce the pressure rating of the connection below those stated in this standard; details are provided in section 4.2.

Freon^®, Heating, Ventilating and Air Conditioning (HVAC), and low pressure (less that 150- psig) water tubing systems are not governed by this standard. Facility compressed air systems operating at 150 psig or less and vacuum systems are not governed by this standard. Refer to International Association of Plumbing and Mechanical Officials (IAPMO), Uniform Plumbing Code (UPC), American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) standards, and applicable Central Engineering Files (CEF)-issued SSC piping system standards and specifications.

Existing designs are not required to comply with this standard except that any modifications or changes to the existing designs shall meet the minimum requirements of this standard.

The government reserves the right to witness or inspect any aspect of the fabrication, cleaning, inspection, testing, and packaging of the tubing, tube fittings, and other related products and services governed by this standard.