Document Lpb6Q4O9xYEmbjB1Mz9wdmg5b

American Society of Heating and Ventilating Engineers Guide.IH? Example S. Assume that the heating units shown in Fig. 26 are handJing 50,000 ctn of air and that the rise in the first row is from 0 to 40 F, in the.second row from 40 to 65 F, and in the third row from 65 to 80 F. What is the load in EDR on each suppj,, and return connection? ' Chapter 32--Piping for Steam Heating Systems The pipe sizes would then be based on the length of the run and the pressure drop desired as in the case of radiators. It generally is considered desirable to place the indVect heating units on a separate system and not on supply or return lines connected to general heating system. DRIPPING Any steam main in any type of steam heating system may be dropped to a lower level without dripping if the pitch is downward with the steam flow. Any steam main in any heating system can be elevated if dripped (Fig- 27)- Steam mains also may be run over obstructions without a change in level if a small pipe is carried below the obstruction to care for Fig. 27. Dripping Mats 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, R 50,000 X (40 - 0) 220.8 9058 sq ft. For row 2, R 50,000 X (65 - 40) 220.8 = 5661 sq ft. For row 3, R 50.000 X (80 - 65) 220.8 3397 sq 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 Loada (EDR) Connection LoAob (EDR) i 9058 2265 2265 or 1132 2 5661 1415 1415 or 708 3 3397 aOne quarter of total row oad. . 849 849 or .425 >One half of stock load if two steam connections are made; otherwise, same as stock load. 596 Fig. 30. Methods of Taking Branch from Main Angle B Constant up zzp 5.126 2.613 30 2J000 45 1.414 60* 1.155 To find length C-multiply A by constant for angle B Fig. 31. Constants for Determining Length Offset Pipe Fig. 32. Dirt Pocket Connection the condensation (Fig. 28). Return mains may be carried past doorways or other obstructions by using the scheme illustrated in Fig. 29; in vacuum systems it is well to have a gate 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 are usually made about 5 ft long to provide flexibility for movement in the main. Offsets in steam and return piping should preferably be made with 597