UL-651:2011 pdf free download – STANDARD FOR SAFETY Schedule 40, 80, Type EB and A Rigid PVC Conduit and Fittings.
6.1.3 Unless otherwise specified all specimens for each of the performance tests in this standard shall be preconditioned for at least 24 hours, in still air, at a temperature of 23.0 ±2.0°C (73.4 ±3.6°F).
6.2 Tensile strength
6.2.1 Preparation of specimens
6.2.1.1 General
6.2.1 .1.1 The average tensile strength of three aged specimens of finished rigid PVC conduit shall equal or exceed 95 percent of the average tensile strength of three unaged specimens of conduit. The procedures (similar to those described in the Standard Test Method for Tensile Properties of Plastics, ASTM D 638) for preparing and conditioning the specimens, for making the measurements, and for calculating the average tensile strengths are indicated in 6.2.1 — 6.2.3. The average tensile strength of the unaged specimens shall comply with the limit established for the compound used but, in any case, shall not be less than:
a) 5,000 psi (34.5 MN/m2) (3.45 kN/cm2) (3515 gf/mrn2) for Schedule 40 and 80 rigid PVC conduit and
b) 4000 lbf/in2 (27.6 MN/rn2 or 2.76 kN/cm2 or 2812 gf/rnrn2) for Type A and EB rigid PVC conduit.
6.2.1.1.2 Six specimens are to be cut from sample lengths of each trade size of finished conduit. Each cut is to be made in a plane perpendicular to the longitudinal axis of the conduit. Each trade size is to be tested on the available power-driven machine. Each sample of:
a) Schedule 40, Schedule 80, Type A conduit is to be 15 inches (380 mm) long;
b) Each sample of Type EB rigid PVC conduit is to be minimum 8-1/2 inches (216 mm) long.
6.2.1.1.3 Measurements are to be made by means of two machinist’s micrometer calipers, each with a ratchet and a flat-ended spindle. The calibration of the scale on each caliper is to facilitate estimation of each measurement to 0.0001 inch or 0.001 mm. The anvil is to be:
a) Hemispherical on the caliper used for thickness measurements of each sample of Schedule 40, Schedule 80, Type A and EB rigid PVC conduit and
b) Flat on the caliper used for diameter measurements of each sample of Schedule 40, Schedule 80 and Type A rigid PVC conduit.
6.2.1.1.4 The rigid PVC conduit is to be smooth and clean wherever it is touched by a spindle or anvil. White measurements are being made, the conduit and the air around it are to be in thermal equilibrium with one another at a temperature of 23.0 ±2.0°C (73.4 ±3.6°F).
6.2.1.1.5 The wall thickness is to be measured at each end of each specimen by means of the caliper with the hemispherical anvil. At least four measurements are necessary at each end to make certain that the thickest and thinnest parts of the wall are found. Each measurement is to be estimated to the nearest 0.0001 inch or 0.001 mm and recorded. The average of all of the recorded thicknesses is to be determined to the nearest 0.001 inch or 0.01 mm for each specimen and recorded as T.
6.2.1.2 Schedule 40 and 80 and Type A
6.2.1.2.1 The outside diameter is to be measured at the center and each end of each specimen of Schedule 40, Schedule 80 and Type A conduit by means of the caliper with the flat anvil. At least four measurements (every 45 degrees) are necessary at each location to make certain that the largest and smallest diameters are found. Each measurement is to be estimated to the nearest 0.0001 inch or 0.001 mm and recorded. The average of all of the recorded diameters is to be determined to the nearest 0.001 inch or 0.01 mm for each specimen and recorded as D.