TEST GAS EQUIPMENT

The GDS Defender is our most cost effective gas detection solution. The control unit has an advanced design using the latest technology, with versatility to accommodate numerous environments such as swimming pools, breweries and car parks. The GDS Defender also has the capability to form part of our Combi CANbus addressable network therofre, offering the features of our most advanced gas detection system.

FIXED SENSOR TESTING

Using an appropriately sized gassing cap fitted directly to the sensor, or for high level detector heads via an extendable gassing pole fitted with the cap, apply test gas to the sensor at a preferred flow rate of 1±0.5 litre/min. Gas applied above this rate may cause the sensor cell reading to be unstable due to the cooling effect and change in pressure (gassing caps have exhaust ports to reduce this effect). When using an extendable gassing pole, the flexible connection tube to the test gas cylinder should be allowed to run up the inside of the pole as it is extended.

Test gas should be applied until a maximum steady reading isachieved on the gas monitor display. At this time, any monitorreading should be corrected before removal of the gas.

The response time period is expected to be within approximately 30 seconds. For specific cell times, appropriate data sheets should be referenced for T90 response times.

It should be remembered that the test gas travel time along the applicator tube, whether it is fixed, portable or through a gassing pole, should be allowed for.

Sampling Systems

For sequential and single line sample systems where the sensor unit is located at the control/monitoring device, it is a requirement that the sensor be calibrated and periodically the integrity of the sample lines be confirmed.

GAS TESTING

For sequential and aIt is expected that the sensor be gas checked at the controller by allowing test gas to be drawn directly from a gas bag until a maximum gas value read-out is obtained. Alternatively, where an adjustable high rate test gas supply is available, this can be applied directly as for fixed sensors, or by the use of an excess blow off tee union. Both methods will allow the pump to operate without restriction.single line sample systems where the sensor unit is located at the control/monitoring device, it is a requirement that the sensor be calibrated and periodically the integrity of the sample lines be confirmed.

Where low flow rate pumps are used (less than 1 litre/min), the sensor may be gas tested directly using the cylinder/regulator supplied with the GDS Test Gas Kit.Having carried out a sensor gas check, the above procedure should be repeated at each sampling point.

FLOW RATE INTEGRITY TEST

Alternatively the sample line integrity may be checked by recording each line flow rate at the control monitoring device followed by a flow rate check at the end of each line, both line readings should be identical.

Sample systems are deployed generally in situations where it is not practical to use wired sensors for a variety of reasons; one of which is inaccessibility to the target area, in such situations where it is not possible to apply test gas to the sample intake point, a thorough inspection of the sample line should be made.

CTS Sample Systems are designed to monitor for sample line blockages but are not able to detect any change in the porosity of the line. In some cases, it may be prudent to incorporate a test gas injection /flowrate test point at the most extreme accessible position in the line.

For Micropore sampling networks, where sample intake modules are arranged in zones or groups and at varying heights depending upon the density of the target gas, the main sample draw line to each module group should be tested as described above with close inspection being carried out of individual intake modules