Tuesday, 29 March 2011
The Importance of Portable Bump Testing
It’s important to do a bump test before you use your portable device, even if it has been recently calibrated. This is the only way to ensure accuracy and ensure that the device will alarm when exposed to specific quantities of gas.
Why bump testing?
Imagine the following scenario; an operator picks up his portable device, which has just been calibrated. He is scheduled to undertake some sandblasting of rusted pipe work in a confined space onboard a ship.
The area he is working in poses a potential hazard for H2S, Oxygen depletion, CO and flammables and his portable device uses catalytic bead detection to monitor for flammable gases. Whilst undertaking the sandblasting, his device is bombarded with minute particles, and some get forced into the sensor’s sinter, partially blocking it up. This means that the sensor is no longer working correctly.
According to his usual equipment maintenance schedule, the engineer does not plan to re-calibrate the device for 3 months. When he next uses the device, he assumes it is working well, but in reality its ability to detect flammable gases has been severely compromised.
Bump testing explained
As the previous example highlights, regular bump testing is essential to ensure that a device is online and able to do the job it is designed to do every time it is used by an operator. There are two main ways to bump test a portable device:
1. Manual method: This involves using a 4-gas mix cylinder (four gases that are being monitored all contained in one pressurised cylinder) and a bump testing kit, consisting of a gas flow regulator and tubing. The operator uses the tubing and regulator to expose the device to the mix of gas from the canister.
2. Automatic method: This involves using a device that provides automatic portable test and calibration. Typically these devices contain an integrated gas supply and easy dock aspect that allows a portable to be tested and calibrated in a few minutes, at the touch of a button.
What’s the benefit?
The table below provides a good comparison for manual testing and automatic testing, but how does this translate into customer value in terms of cost savings?
When it comes to time management, even the smallest changes can equate to considerable savings over time. A small change such as reducing the bump test time from five minutes to two minutes can translate into a labour cost reduction of 60%. When additional aspects such as auto data logging and auto calibration are also included, this percentage rises to an approximate saving of 75% by making small time efficiencies.