HLY-GEN-01: Three-Edge Bearing Load Testing & Hydrostatic Proof Standards

1. Three-Edge Bearing Test (TEBT, ASTM C497 / GB/T 16752)

Apparatus Setup: Rigid loading frame, upper loading beam, lower parallel hardwood timber strips (width 50 mm, spaced at 1/12 of internal pipe diameter, min 25 mm).

0.2 mm (0.01-in.) Crack Proof Load:

- Apply load at a uniform rate up to proof requirement; sustain for 1.0 minute;
- Inspect full length using a calibrated 0.20 mm leaf feeler gauge (penetration limit 1.5 mm); passing criteria: max crack width $\le$ 0.20 mm.

Ultimate Proof Load: Continue loading until ultimate criteria; pipe must support load without collapse.

2. Hydrostatic Impermeability Proof Testing

Seal both pipe ends using bulkheads with inflatable gasket seals; fill with water, venting air.

Pressurize to 0.10–0.15 MPa; hold steady for 10–15 minutes;

Full external surface must show zero water beading, sweating, or pressure decay $>0.01$ MPa.