Landtec Tab > Landtec_GA5000 Machines > CEMEX Instructions for taking Gas Flow Readings

The following section describes the way in which gas flow readings must be taken to comply with the CEMEX requirements.

There are a number of different parameters that can be used to measure gas flow. These are instantaneous, peak and average over a period of time. CEMEX require the use of the

AVERAGE FLOW OVER a 1 MINUTE PERIOD – at all locations and at all sites

Set this parameter on your gas machine NOW and it should continue to do this for all future readings BUT remember to reset this if it has changed following a service.

1)Select SPECIAL ACTION option - Select option 4 for FLOW - Select FLOW OPTIONS

2)Press Button 1 until screen shows Flow Options of AVERAGE (i.e. NOT Snapshot or Peak)

3)Press Button 2 for Duration (mins) and Press 1 (for 1 mins)

4)Press Enter then Press Exit

Order of taking gas readings

1)Gas Flow – Average flow in 1 minute – l/hr

2)Relative Pressure

3)Gas Concentration

4)(Water Level if appropriate)

Methodology

1)Gas Flow Reading

a)Move the clear sampling tube to the BLUE PORT in the Top of the machine – BUT DO NOT CONNECT IT TO THE SAMPLING POINT

b)Select SPECIAL ACTION option - Select option 4 for FLOW

c)Select ZERO FLOW OPTION to zero the flow

d)Connect tubing to the Sample Point and open Gas Valve

e)Select START button – the machine will count down from 1 minute to zero – WAIT until it is finished.

f)Select STORE button, and the machine will return to the Gas Reading Screen with a Fixed Internal Flow Reading

g)Close Gas Valve temporarily.

2) Relative Pressure Reading

a)Disconnect all Tubing from the Sample Point

b)Select Relative Pressure on the Gas Machine menu

c)Move the clear sampling tube to the WHITE PORT in the Top of the machine – BUT DO NOT CONNECT IT TO THE SAMPLING POINT

d)Select ZERO to zero Relative Pressure whilst not connected to sample point.

e)Connect Clear tubing to the sample point and open gas valve.

f)Select NEXT and it will return to the Gas Reading Screen with a varying Relative Pressure value –

g)Allow Relative pressure reading to settle and press NEXT to ACCEPT stable pressure reading.

3) Gas Readings

a)Select Gas Readings

b)With the CLEAR tubing still connected to the WHITE PORT and to the Sample Point.

c)Press NEXT and the pump will turn on and allow gas readings to stabilise – at least 30 seconds, MORE for the deeper gas samplers or larger diameter boreholes.

d)Fix Gas Readings once stable by pressing NEXT

Select STORE to store all GAS READINGS