What Is A Bump Test In Gas Detection?

A bump test or bump check is a quick test of your gas detectors to ensure they function as intended. It checks that the sensors and alarms are working correctly by briefly exposing the detector to a known gas concentration.

Table of Contents

Types of bump test

There are two types of bump tests: manual bump tests and automated bump tests.

Manual bump test

This bump test is performed manually, meaning that it is performed without a docking station.

This method does not require extra equipment, which is useful if you have a few gas detectors.

Automated bump test

This is when you are using a docking station to bump test your gas detector; this method makes it very easy to test your gas detectors.

The disadvantage of this method is that you need to buy a docking station or bump test station, which can add extra cost.

It is probably not worth it if you have few detectors, but it can become a wise investment if you have many gas detectors.

Having a docking station makes the bump test quick, it will save you money since there is few bump test gas lost during calibration and you can set the bump test once and use the same settings to test all your gas detectors.

What accessories do I need to perform a bump test?

To perform a bump test in one of your gas monitor requires the following equipment:

A gas detector to bump test

Although it sounds obvious, you need a gas detector to bump test. This can be a portable or fixed gas detector.

Calibration cap or adaptor

This cap or adaptor ensures the gas is trapped and directed to your gas detector’s sensors. This is for diffusion gas detectors, for pumped ones probably you will need a quick connector.

Tubing

The main function of the tubing is to capture and funnel the gas toward the air monitor. Usually, it is between 1 to 4 feet.

Calibration gas

This is the calibration gas you need to bump-test your sensors. It must be the same as your gas sensors, and its concentration should be above the lowest alarm.

Optional Docking station

You need a docking station for an automatic bump test, but this is optional since the bump test can be done manually.

If one exists for your monitors, a docking and calibration station could help keep your equipment in one place and make calibration and bump testing more convenient.

A demand flow regulator is also needed for a docking and calibration station.

How to bump test a gas detector?

Step 1: Turn on the monitor.

Step 2: Connect the regulator to the gas cylinder.

Step 3: Connect the tubing or calibration hose.

Step 4: Connect the calibration cap to the instrument. If it is a pumped instrument, it will have a quick connector, which you need to attach to the hose.

Step 4: Open the valve or knob in the regulator.

What Is an Acceptable Bump Test Result?

A bump test is a functional test to ensure the gas sensors work as they should. The recommendation is that the gas concentration used in the bump test should be enough to trigger at least the lowest alarm level.

This will ensure that you test whether the sensors are functional and also test the audible and visible alarms.

The reading on the screen will not always perfectly mirror the specs on the bottle of target gas, but as long as the variation is within 10%, we can consider the monitor to function within the acceptable range.

If the sensors do not read the gas to the required range or the alarms are not activated, consider the bump check failed.

Why will a gas detector fail a bump test?

A bump test could fail for several reasons, and it’s not always because the unit is defective or broken. Here are some reasons why the gas detector might fail the bump test.

Extreme shock

If a gas detector falls from a significant height or onto a hard surface, the sensor cannot operate correctly and fails the bump test.

Extreme temperature changes and weather conditions

Gas detectors are designed to work under certain conditions, always indicated in the unit or the detector’s datasheet.

Exposing a gas detector to hot or cold temperatures can affect the sensor’s sensitivity.

Excessive exposure to dust

Sometimes, we use gas detectors in dirty environments, which can cause physical blocks in the detectors.

These blocks can cause the sensor to become less sensitive to gas in the surrounding atmosphere.

What do if a gas detector fails a bump test?

If your gas detector fails calibration, do the following.

Verify whether the calibration gas has expired.

Most calibration gas cylinders will have a sticker that says use by or expiration date; make sure that the date has not passed and that the bump test gas has not expired.

Check if you are using the right regulator.

There are two types of bump tests: manual and automated bump tests. In manual calibration, we use a constant flow regulator that has a knob we use to open and close the gas during the bump test.

If you are using a docking station, the demand flow regulator is used; this will make the regulator open or close in an automated way using the vacuum generated by the docking station.

Mixing these two types of regulators can cause your bump test to fail; if you are not sure which regulator to use, please call the detector manufacturer. They should be able to guide you.

Try the manual bump test if you use a docking station.

If you are using a docking station to bump-test your gas detector and it fails, try to do it manually; if it passes, troubleshoot the docking station.

Swap the sensors

If you have tried all the above and the sensor still fails, swap the sensors. If you have another working sensor, try swapping it with the one you are bump testing.

If the bump test passes, it is a sensor issue. If it still fails, it is time to troubleshoot the detector itself.

What to do is the gas detector fails the bump test with the docking station but passes a manual bump test?

If the fas detector passes the manual bump test but fails the bump test with a docking station do the following.

Clean the IR terminal in both the docking station and the detector

When you put your gas detector into the docking station there is a contact between the two instruments which is done through an IR plate.

You can take a dry and clean cloth, and clean the plates in both the detector and the docking station, then try again to perform a bump test.

Test with a different detector

If you happen to have another detector or docking station, try to swap them, this is the easiest way to locate where the issue is.

If the issue goes with the detector, it is the gas detector that has the issue, if the issue persists within the the docking station while you are testing with a different gas detector, the docking station needs to be serviced.

Service the docking station

If after the swapping exercise, you discover that the issue is with the docking station, you need to service it.

The issue is that docking stations have small sound sensors inside, the main function of these sensors is to detect the sounds so that the docking station can determine if your detector is beeping or not during the bump test.

If these sensors are damaged, the bump test will always fail.

Only a licensed technician should service the docking station or a gas detector.

The Importance of Bump Testing

Safety Assurance

A bump check provides your instrument with safety insurance. It is essential to trust that a gas detector will alert you to the presence of a harmful agent. A bump test is a quick check that gives this assurance.

Detection Reliability

Sensors can lose sensitivity due to regular exposure to specific chemicals or physical damage. Regular bump testing identifies sensors with reduced sensitivity.

The law requires it.

Many safety regulations and standards, both international and domestic, require regular bump testing of gas detectors. Compliance ensures safety and avoids potential legal and financial penalties.

FAQ: What Is A Bump Test In Gas Detection?

When to bump test a gas monitor?

We recommend doing a bump test before each use for intermittently used detectors and portable monitoring devices, which are often powered off and on and used in changing environments.

A full calibration must be performed if the bump test results are not within the acceptable range.

Why is bump testing important?

Bump testing involves quickly testing your portable gas detectors to ensure they function as intended.

The bump test checks that the sensors and alarms are working correctly by exposing the detector briefly to a known gas concentration.

What is the difference between a bump test and a calibration?

A bump test verifies the sensor and alarm functionality by briefly exposing the sensors to a known gas concentration, ensuring they respond correctly.

On the other hand, calibration adjusts the sensors to measure gas concentrations accurately, compensating for sensor degradation over time.

How do you do a bump test?

A bump test is a simple process where you expose sensors in a gas detector to an expected gas concentration greater than the alarm set points. If everything works as expected, the gas detector will go into alarm.

Key takeaways: What Is A Bump Test In Gas Detection?