EN 917-1997 pdf download.Plastics piping systems Thernioplasties valves Test methods for resistance to internal pressure and leaktightness.
2.3 closing torque
‘R)rque rvqtiired IL) close a valve to full tightness at the nominal pressure. It is usually expressed in newton nwtres.
3 Method A: Long-term pressure test
3.1 Principle
A complete valve assembly with its connections is subjected to constant internal pressure at a constant temperature for a period which has to be specified to verify that the design of the valve and its connections do not advene1y affect the long-term behaviour performance of the valve.
NOTE 1. For component pressure testing on a valve body (shell test), ISO/hIS 12092 can be used.
The internal pressure is applied using water. The external environment can be air or water.
After assembly and conditioning as appropriate, test pieces are subjected to a specified constant internal I)ressllre for a specified period of time or until the test 1)Iece fails. While under iwessure the test pieces are kept in an environment at a specified constant temperature.
NOTE 2. It Is assumed that the following test parameters are set by the standard making reference to this standard:
a) the test temperature (see 3.2.1);
b) the test pressure (see 3.2.2);
c) the time under pressure (see 3.2.2);
d) any performance requirements including, if applicable, the criteria for a loss of pressure indicative of failure (see 3.2.5);
e) the number of test pieces (see 3.3.2).
3.2 Apparatus
3.2.1 Tank, filled with water kept at a temperature as specified hi the referring standard to within ± 1 C, or a testing room having au air temperature kept within
T of the temperature specified in the referring Stafl(lard.
‘%Y1E. As 11W ri-siilts are strongly inlltwiiceil by temperature, the tolerance on tenhlwrdture should be kept as small as possible within the specified limits.
3.2.2 Pressurization equipment, capable of:
— progressively applying the pressure specified in the referring standard;
— maintaining this pressure with a deviation not exceeding % for the period of time specified in the referring standard.
3.2.3 Pirssu r’ .‘neasu irinenl cte jees, capal)le of checking confonnity to the specified test pressure. In
the Case of calibrated gauges or similar iiIre measurement devices, the range of the device shall be such that the required pru setting shall lie within (lie cahL)rated range of the (k?vlce used.
The pressure measurement device(s) shall not contanthiate the test fluid.
NOTE. The use of master gauges for calibration of the apparatus is recommended.
3.2.4 77crm onu’(crs or equ 1 vakn 1, capable of checking conformity to the specified test temperature.
3.2.5 Thuci; capable of recording the duration of the pressure application UJ) to the moment of failure of the test piece, as specified by the referring stan(lar(L
3.3 Test pieces
3.3.1 Assembly of test pieces
Each test iiece shall comprise a complete valve with all colutectrng elements assembled in accordance with the valve maiiufaclurer’s instructions and the following requlrenlents, as applicable.
a) Valves with flanges or unions.
The test piece shall be connected by meais of flanges or tuiions to the test apparatus.
b) ilves with threaded ends.
The test piece shall be connected by iiieis of threaded fittings to (lie test apparatus.
c) Valves with ends for fusion or solvent-cement joints.
Tue test piece shall lw connected by fusion or solvent cementing to thermoplastics pipe sections. l’he minimum free length of the pipe sections shall be at least equal to (lie outside diameter of the pipe. The pipe shall be cut at right angles to its longitu( linal axis.
d) Valves with compression-fitting ends. The test piece shall be connected to appropriate pipe sections. The niininmiu free length of the pipe sections shall be at least equal to the outside (haifleter of the 1)11W.
e) Valves with elastomeric sealing ring type socket joints.
The test piece shall be connected to appropriate pipe sectIons. The minimum free length of the pipe sections shall be at least equal to the outside (hanleter of the 1)11W.
The curing or setting time for moulded, fused or cemented coniponents specified by the manufacturer shall be completed before conmlencing conditioning in accordance with 3.4.
3.3.2 Number
The number of test pieces shall be as specified in the
referring standard.
3.4 Conditioning
For conditioning before or after 3.5.3, fill the test piece with water and condition it. for at. least 1 h at a temperature not deviatuig more than ±5 C from the specified test temperature (see note 2 to 3.1).
3.5 Procedure
3.5.1 Prepare a test piece in accordance with 3.3.
3.5.2 Before or after 3.5.3 or 3.5.4. as convenient, condition the test piece in accordance with 3.4.EN 917-1997 pdf download.