Iowa Code r. 875-92.9 - Pressure gage requirements
This rule applies to power boilers installed prior to July 1, 1983. Each boiler will have a pressure gage so located that the gage is readable. The pressure gage will be installed so that it will at all times indicate the pressure in the boiler. Each steam boiler will have the pressure gage connected to the steam space or to the water column or its steam connection. A valve or cock will be placed in the gage connection adjacent to the gage. An additional valve or cock may be located near the boiler providing it is locked or sealed in the open position. No other shutoff valves will be located between the gage and the boiler. The pipe connection will be of ample size and arranged so that it may be cleared by blowing out. For a steam boiler the gage or connection will contain a siphon or equivalent device that will develop and maintain a water seal that will prevent steam from entering the gage tube. Pressure gage connections will be suitable for the maximum allowable working pressure and temperature, but if the temperature exceeds 406 degrees F, brass or copper pipe or tubing will not be used. The connections to the boiler, except the siphon, if used, will not be less than 1/4-inch standard pipe size, but where steel or wrought-iron pipe or tubing is used, they will not be less than 1/2-inch inside diameter. The minimum size of a siphon, if used, will be 1/4-inch inside diameter. The dial of the pressure gage will be graduated to approximately double the pressure at which the safety valve is set, but in no case to less than 11/2 times this pressure.
Notes
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