Document k952v5EXjdpvgBV9ZgpbYYBY0

To: J. D. Olson A From: M. G. Schneider Dote: August 6, 1991 Subject: BREATHING AIR SYSTEM MODIFICATIONS - REVISED FINAL ISSUE VISIA Attached is the BREATHING AIR SYSTEM MODIFICATIONS Design. The last issue of this design completed on May 13, 1991 has been modified. The May 13 issue installed an unloading device for the breathing air compressors, however after discussion it was determined that the compressors could be started and stopped instead of installing an unloading device. This will reduce the scope of the project and increase the savings due to the project. Instead, A pressure switch (PS-101) will activate the breathing air compressors. When the pressure in D-101 falls to 30 psig a Breathing air compressor will start up. When the pressure in D-101 gets to 45 psig that breathing air compressor will stop. PS-101 will also activate the potable water supply control valve NV-103. A timed relay for the potable water supply control valve NV-103 will be installed. This will provide water to the compressors and its seals to allow for adequate water supply during the startup of the compressor. The water will be cut off with the compressors, however the water supply valve will open 5 seconds before the compressors are activated. Check valves CV-101, CV-102, CV-103, CV-104 will still need to be installed on the header line between the breathing air compressors and D-101. These check valves are to prevent the loss of pressure back into the unactivated compressor. The updated drawing is attached to the back of this design. If you have any questions please contact me at 3617. Michael Schneider Co-Op Process Engineer CC: RWS, DCS, RBN, DAM, MLC, JBA, KJA, SCH, MRK, DEK, JBH VAB.0001149664