Therefore, pipes may have the same nominal diameters (outside diameters) but with different
inside diameters because of the different schedule numbers.
The usual schedule numbers are 10, 20, 30, 40, 60, 80, 100, 120, 140 and 160 with the thickness
increasing with the numbers.
These numbers are further classified as Standard (ST), Extra Strong (XS) and Double Extra
Strong (XXS) whereby applications requiring higher pressures will need pipes with thicker walls.
However, in the HVAC industry and for our mini chiller installation, a standard schedule 40 pipe
will suffice.
The steel pipes may be joined by several methods:
1. Arc welding
2. Thread (usually up to 50mm) with PTFE Teflon white tape
3. Flange with gaskets
2. Copper Pipes
Copper pipes are chosen for water piping because of their resistance to corrosion and ease of
installation. The pipes are light and ductile.
However, the cost of these pipes are higher compared with steel pipes (generally by 3 -
5 times).
The sizes of these copper pipes are defined by the ASTM (American Society for Testing and
Materials) standard B88 for water and drain services. See Appendix 2.
There is also another ASTM standard B280 which specifies the sizes of pipes used for
refrigeration services with different wall thickness. This standard uses the outside diameter as
the nominal size.
These pipes are also generally sold in lengths of 6 meters.
Generally, the B88 standard defines 4 types of copper tubes: Type K, L, M and DMV with
descending wall thickness. The most commonly used types are type L and M which have higher
internal working pressures. These may be of hard drawn or soft annealed temper.
The copper pipes may be joined by:
1. Brazing
2. Soldering
3. Flare joint / compression joint fittings
Section: 3
Page 29
Summary of Contents for AC 40A
Page 1: ...AM MAC ...
Page 153: ...Appendix 1 ...
Page 154: ...Appendix 2 Appendix 2 ...
Page 157: ...GRAPH OF PRESSURE DROP VS FLOW FOR VARIOUS C V RATINGS Appendix 5 1 ...
Page 158: ......
Page 159: ...Water Capacity Graph Appendix 5 2 ...
Page 160: ...CHART 3 FRICTION LOSS FOR CLOSED PIPING SYSTEMS Appendix 6 1 ...
Page 161: ...CHART 4 FRICTION LOSS FOR OPEN PIPING SYSTEMS Appendix 6 2 ...
Page 162: ...CHART 5 FRICTION LOSS FOR CLOSED AND OPEN PIPING SYSTEMS Appendix 6 3 ...
Page 168: ...Appendix 8 Appendix 8 ...
Page 169: ...Appendix 8 1 ...
Page 170: ...Appendix 8 2 ...
Page 171: ...Appendix 8 3 ...
Page 172: ...Appendix 8 4 ...
Page 173: ...Appendix 8 5 Appendix 8 5 ...
Page 174: ...Appendix 8 6 Appendix 8 6 ...
Page 175: ...Appendix 8 7 Appendix 8 7 ...
Page 176: ...Appendix 9 ...
Page 178: ...Appendix 11 1 Appendix 11 1 ...
Page 179: ...Appendix 11 2 Appendix 11 2 ...
Page 180: ...Appendix 13 ...
Page 181: ...Appendix 13 1 ...
Page 182: ...Appendix 14 Appendix 14 ...
Page 183: ...Appendix 15 1 Appendix 15 1 ...
Page 186: ...Appendix 17 Appendix 17 ...
Page 187: ...Appendix 18 ...
Page 188: ...CE20DW CE25DW Note PRESSURE DROP CORRECTION FACTOR 1 2947 0 0021 EWTºF Appendix 19 ...
Page 189: ... 2003 McQuay International 603 55194922 www mcquayup com ISO 9002 REGISTERED ...
