Measuring hydrogen, 3 gas detectors for working safely
You want to measure hydrogen and are looking for the solutions available today. That is why BaSystemen describes in this article:
- Hydrogen, what is it and where do you encounter it?
- What are the hazards of hydrogen?
- What does Dutch legislation say about working with hydrogen?
- Measuring hydrogen, present-day solutions
What is hydrogen?
Hydrogen, also known as H2 (so in fact dihydrogen), is colourless, odourless and tasteless, and in this article we mainly refer to hydrogen in its gaseous state. Hydrogen is the most abundant element in the universe, and is also found on earth in large quantities. Hydrogen is exceptionally reactive: you find its atoms back in NH3, H2S, CH4 (and many other hydrocarbon compounds), but also in H2O, for example. That last substance is also the reason why we hardly ever encounter hydrogen in its pure form: H2 bonds extremely quickly with an oxygen atom, forming water.
Other properties of hydrogen are its high flammability, its low atomic mass and …..
- Flammability: Hydrogen is highly flammable, just like methane, for instance, which comes out of our gas hob. A mixture of hydrogen and air can ignite easily. If a space contains between 4% and 75% hydrogen, this forms an explosive mixture together with the air. By way of comparison: natural gas is only flammable in a mixture of between 4.4% and 15% natural gas in air. In addition, hydrogen has a low ignition energy of 0.02 mJ. This means that a small spark can already be enough to cause an explosion. By way of comparison: methane has an ignition energy of 0.29 mJ.
- Low atomic mass: Hydrogen has a very low atomic mass (1.0079 grams/mol). This makes hydrogen the lightest element on earth, which means that it rises quickly. One advantage of this is that it disappears relatively quickly in a well-ventilated space or in the open air (through ventilation grilles, or through its high reactivity with oxygen, for example). A disadvantage is that hydrogen can build up quickly in a poorly ventilated space and can create a risk of explosion.
Where do you encounter hydrogen?
As said earlier, hydrogen is a very common element. On the other hand it is extremely volatile and therefore also gone again in no time. Measuring hydrogen is certainly not simple either. That is why it is always a good idea to map out where the sources are, so that you can measure in a more targeted way. In recent years hydrogen has grown enormously in popularity again and at BaSystemen we receive questions about measuring hydrogen from a range of sectors. These come mainly from the following sectors:
Oil & gas
This often concerns sectors where hydrogen is produced as an alternative fuel. The oil and gas sector has been in transition from fossil energy to more sustainable sources, including hydrogen, for many years. There is certainly still room for debate about grey or green hydrogen, but we will not expand on that further in this article.
Research & Development
Because hydrogen is increasingly being included in plans for large-scale application in the future, a great deal of research has been carried out for years. In the Netherlands too we receive more and more questions from renowned parties conducting research into measuring hydrogen in test set-ups, for example;
- Homes and buildings connected to hydrogen instead of natural gas
- Vehicles powered by hydrogen and therefore also refuelling solutions for hydrogen
- Storage and transport of hydrogen
- Production of hydrogen by means of electrolysis
Battery charging rooms
By battery charging rooms we mean an environment set up for charging (the batteries of) electrically powered equipment. One of the best-known examples is a charging room for electric forklift trucks. Hydrogen can be released while batteries are charging, and in small, poorly ventilated spaces this can cause a build-up of hydrogen gas, which means a hydrogen detector is not a bad idea in this type of space either.
What does Dutch legislation say about working with hydrogen?
As with most specific gases, the Dutch Working Conditions Act (Arbowet) does not deal specifically with hydrogen gas. However, as mentioned several times above, hydrogen can create a risk of explosion, and on that subject the Working Conditions Act does of course have more to say.
The Working Conditions Decree covers the European ATEX 153 Directive in Articles 3.5a to 3.5f of the Working Conditions Decree . Under the Working Conditions Act the employer is in fact obliged to pursue a policy aimed at protecting employees against the risk of explosion. You must comply with this without question, but it is not the speciality in which BaSystemen can help. If you wish, you can also read our article on the risk of explosion in general.
What does apply to our field is Article 3.5g of the Working Conditions Decree. The following two points in it are certainly worth mentioning:
- Where it may be suspected that the atmosphere in a place or space contains substances to such an extent that this creates a risk of asphyxiation, narcosis, poisoning, fire or explosion, the employee may only be present in that place or space if an investigation shows that the risk is not present.
- Where the investigation referred to in the first paragraph shows that a risk of asphyxiation, narcosis, poisoning, fire or explosion is present, effective measures shall be taken so that the employee can be present without danger in that place or space referred to in the first paragraph.
- There is in any event a risk of fire or explosion if the concentration of oxygen in the atmosphere is higher than 21 per cent by volume, or the concentration of flammable gases or vapours is higher than 10 per cent by volume of the lower explosive limit.
Briefly summarised in plain language:
- Before entering a space where hydrogen gas could be present, you must know whether and how much hydrogen gas is present in that space. This can be done with permanent hydrogen detection inside the space, from which you can read the values outside the space. A second option is to measure hydrogen with a portable gas detector that draws in gas from the space concerned using a pump. From the measured values you can determine whether you can safely enter. But that is not all…
- Secondly, the employee entering the space must equip themselves with a personal gas detector, so that they are also protected while working in the confined space. Unless, of course, the space is fitted with permanent hydrogen detection.
Measuring hydrogen, present-day solutions
At BaSystemen we receive more and more questions about measuring hydrogen, hence this article as a starting point. Should it still leave you with questions, feel free to call us on +3150 571 2124 or send an e-mail to info@basystemen.nl.
We have a great many instruments that measure hydrogen, so we cannot cover them all. The most common ones are briefly described below:
1. Simple hydrogen detector
The MicroRAE is a multi-gas detector that can be fitted with a catalytic LEL sensor. The device is attached to workwear or to a belt with a crocodile clip. This sensor can measure hydrogen and can even be calibrated specifically for hydrogen. Optionally, this device can be extended with sensors for oxygen, hydrogen sulphide, carbon monoxide or hydrogen cyanide. As soon as the hydrogen level rises above 10% LEL, as described in the legislation above, the MicroRAE will beep and flash to alert the user.
2. Transportable area monitor
The RigRat is an area monitor which, like the MicroRAE above, can measure several gases simultaneously. But it can equally well be fitted with just one sensor to measure hydrogen at LEL level. The RigRat is an area monitor that can be set down as a so-called ‘mushroom’ or ‘watchdog’ to be placed in a space for a longer period and monitor the presence of hydrogen. The RigRat features data logging, so the measurement data can also be read out afterwards.
3. Fixed area monitoring
The WatchGas XDI F1 is a fixed detector head that can be supplied with a catalytic LEL sensor. By placing several of these sensors strategically, you can measure hydrogen at several points in the space. Now, measuring hydrogen is not that simple because the gas is extremely volatile. It is therefore important to consider carefully where the H2 can escape and, for example, to place a detector head above a valve or connection that could start to leak. BaSystemen is happy to help further with advice and other matters that need to be taken into account
