C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Daya Bay RPC gas system fire safety issue Slides from Gas System FDR + a few more new slides.

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 How Much Gas Should Be Stored Underground? Tradeoff between frequency of transport/changeover of bottles vs. degree of oxygen deficiency hazard and flammable gas hazard from leaks at bottles. A new quote indicates Isobutane in US only has two cylinder sizes: 116 $400.00; 17 unit price almost 2.5 times higher in small cylinder. Use 116 LB cylinder can cut down the gas cost from $52,067/year to $49,609/year. In addition to bottles in use, a second set of bottles should be underground at all times. In the following configuration  54 bottles underground (Red color  IHEP’s cylinder specs, black color  US cylinder specs). Exp. HallGasCylinderDays/90% of cylinder used Near Hall Ar6 #300 R134A90 LB/100kg24/58 Isobutane17 LB/50kg37/240 SF635 LB/4kg243/61 Far hall Ar6 #300 R134A90 LB/100kg15/37 Isobutane17 LB/50kg23/149 SF635 LB/4kg150/38

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 How Much Gas Should Be Stored Underground? (cont’d) We just learned from Dana’s about the quantity allowed in the gas room: “Maximum Flammable gas is 750ft**3. Quantity can be doubled if sprinklers ( ) and Doubled if in approved storage cabinets, gas cabinets or exhausted enclosures.” 50kg Isobutane cylinder is within this limit: 2 such cylinders are needed in each site  100kg Equivalent volume of 100kg Isobutane = g/58g*22.4l/1000l/ = 1365 ft 3 < 2* 750 ft 3. Question: Does the sprinkler itself can double the total allowed flammable gas volume? Does any one of the “approved storage cabinets, gas cabinets OR exhausted enclosures” can double the total allowed flammable gas volume?

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Daya Bay Gas Monitoring System — Logic diagram

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Gas system status crate

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Gas system status crate — Logic diagram

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 HAD Sensor Various brands of HAD sensor can be used to detect % LEL(Low Explosive Limit) for many flammable gases, Isobutane is one of the detectable gases. FYI, the working principle of HAD sensor:

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 HAD sensor (cont’d) One candidate of such HAD sensor is RAEGuard LEL.

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Backup slides

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Cost estimation of the safety crate

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Air ventilation sensor and controller Pt is the total pressure, Ps is the static pressure. Notice the sensing holes for these two pressures. The manometer shown on the left can measure the pressure difference between Pt and Ps, this is Pv, the air velocity pressure. Working principle of using Pitot tube to measure the air velocity. Dwyer model Photohelic 3000SGT pressure transmitter/controller

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Suggested air ventilation scheme To keep the air sweeps every corner of the gas rooms, the air ventilation duct has to be arranged properly. Shown on the left is a sketch of the BaBar gas shack air ventilation system. It shows 4 sensors are installed at 4 critical location: (1) room air source; (2) room air return; (3) exhaust room air; (4) fresh intake air.

C. Lu, K.T. McDonald RPC Gas System Final Design Review April 11, 2008 Our Present Budget Estimate Project Management (W. Sands) $30k System/crate Design (W. Sands, S. Chidzik) $25k 3 mixing panels $75k Control boxes for the mixing panels $25k Input bubbler systems $20k Output bubbler systems $80k Water admixture systems $5k Gas cylinder changeover systems $25k Conversion of 1 st panel from QC to production use $10k or 4rth mixing panel $15k additional Hazardous gas safety system $60k Installation at Daya Bay $16k Archival drawing sets $10k Test, QC/QA $35k Shipping $14k Total $430k = $254k + $176k or $445k = $254k + $191k (red  NOT in present RLS) (blue  in present RLS accounting)