Document wDK294Ep8E87LOypqk981NyY4

Heating Ventilating Air Conditioning Guide 1939 65 F, and in the third row from 65 to 80 F. What is the load in EDR on each and return connection? , ^7 The pipe sizes would then be based on the length of the run and the pressure dmdesired, as in the case of radiators. It generally is considered desirable to place theij Chapter 16. Piping for Steam Heating Systems heating units on a separate system and not on supply or return lines connected to ^general heating system. DRIPPING A steam main in any type of steam heating system may be dropped to a lower level without dripping if the pitch is downward, and with the direc tion of steam flow. Any steam main in any heating system can be elevated 5 dripped. Fig. 27 shows a connection where the steam main is raised and the drain is to a wet return. If the elevation of the low point is above a drv return it may be drained through a trap to the dry return in two-pipe vapor, return, vacuum return line and sub-atmospheric systems. Hori- Fig. 27. Dripping Main Where it Rises to Higher Level Fig. 28. Looping Main Around Beam. Fig. 29. Looping Dry Return Main Around Opening Fig. 26. Typical Piping for Atmospheric and Vacuum Systems with Thermostatic Control (Central Fan System) Solution. For row 1, ,, 50,000 X (40 - 0) _ ^ R = --------- 2208------------- 9058 SQ ft' For row 2, _ 50,000 X (65 - 40) R = --------- 2208--------- = 5661 Sq ft` For row 3, o 50,000 X (80 - 65) _ ,,on, R = -------- 2263------------ 3397 811 ft- Each row of heating units consists of four stacks and each stack has two connections so that the load on each stack and each connection of the stack is as follows: Row Total Load (EDR) Stack Load* (EDR) Connection LoAob (EDR) i 9058 2265 2265 or 1132 2 5661 1415 1415 or 708 3 3397 ;849 849 or 425 One quarter of total row load. bQne half of stack load if two steam connections are made: otherwise, same as stack load. Fig. 30. Methods of Taking Branch from Main To find length C-muiUpty A by constant tor angle B Fig. 31. Constants for Determining Length Offset Pipe out pocket 1V * Wet return Fig. 32. Dirt Pocket Connection zontal steam pipes may also be run over obstructions without a change in level if a small pipe is carried below the obstruction to care for the con densation (Fig. 28). Horizontal return pipes may be carried past door ways and other obstructions by using the scheme illustrated in Fig. 29. It will be noted that the large pipe, in this case, runs below the obstruction and the smaller one over it; in vacuum systems it is well to have agate valve in the air line. Branches from steam mains in one-pipe gravity steam systems should use the preferred connection shown in Fig. 30, but where radiator condensa tion does not flow back into the main the acceptable method shown in the same figure may be used. This acceptable method has the advantage of giving a perfect swing joint when connected to the vertical riser or radia tor connection, whereas the preferred connection does not give this swing without distorting the angle of the pipe. Runouts from the steam main 333