# P5.1: Replacement of N2 or CO2 gas bottles (BT1/BT2)
This section describes the procedure for replacement of gas bottles.
If you receive an alarm on the gas, you need to come to LCSB.
1. A first method to identify which type of bottle is empty is to check on the gas panel in the corridor of the 4th floor in BT1 and room 104, 1st floor in BT2.
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* If one LED is on, one couple of bottle is empty, only one couple of bottles needs to be replaced.
* If two LEDs are on (left and right), both couple of gas bottles are empty and need to be replaced urgently.
2. Press the reset button to stop the beeping.
3. A second way to identify which type of gas and which couple of bottles is empty, is to directly check the manometers in the gas deposit rooms.
If the manometer (5 in the picture below) displays 0 bar, this means that the couple of bottles is empty.
4. If you can see on the “Gas Bottle Exchange Sheet” in the room that the CO2 bottles have already been changed in the 48 h prior to the alarm, this is indicative of a pipeline infrastructure break down → see P6: gas network total failure back up plan.
5. Replace the empty bottles in room 005 of BT1 or LT03 of BT2, ground floor
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|*Personal protective equipment*|
|:-----------------------------:|
|Lab coat|
|Safety goggles|
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* Check the gas level on the manometer (5 on the picture). When empty, it displays 0 bar.
* Once the bottles that need to be changed have been identified, close the network valve (3 on the picture)
* Close the bottles (1 on the picture)
* Open the purge valve (4 on the picture) to release the pressure remaining in the pipe connecting the bottle, then close back the purge valve
* Unscrew the tubing from the bottle by hand (2 on the picture)
* Move the empty bottle to the bottle rack, bring the new bottle and fasten the chain
* Connect the new bottle by screwing the tubing hand tight (2 on the picture)
* Open the gas bottle (1 on the picture)
* Check for leaks at the connection between the bottle and the tubing
* Open the purge valve (4 on the picture) for 2 seconds to fill the tubing with gas and remove the air, then close it back
* Open the network valve (3 on the picture)
6. Check for any leak after connecting the bottle using the leak detector spray located in the gas deposit room, an example is shown on the picture below
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7. Fill up the “gas bottle exchange record sheet” (Appendix 03) on the door inside the gas deposit room. A copy of this document is present in each gas deposit room
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8. Check in the LIMS if the alert is resolved
9. Notify the LCSB duty call manager and their backup by email, fill and fill the:
