Here we selected all the Frequently Asked Questions about Hazcalc such as technical issues, subscriptions and how to perform assessments. Most FAQ's are also clarified within the user manual. Specific assessment issues are integrated within the help function of Hazcalc and can also be found in the user manual that comes with an Hazcalc subscription.


Users must know the general systematics of hazardous area classification and have general knowledge or experience in assessing workplaces. It can be typically used by e.g. SHE Officers, Proces Safety Engineers, Chemical Engineers, inspectors etc. Within the tool there is an extensive help-function available so with every step within the assessment guidance is provided. So in practice, an assessments can be made without any typical knowledge, when the information in de user manual or in the help function is followed. Nevertheless, we always advise to discuss the results of an assessment with an expert in Hazardous Aea Classification.

See the example video:

The General Terms and Conditions for use can be downloaded and printed here:

General Terms and Conditions Hazcalc


Hazacalc can be used on Chrome, IE, Edge and IOS (Mac).

Hazcalc can be used on Windows and Apple machines (laptop / desktop), on tablets and on smartphones. An internet connection is required.

The Technical specifications can be downloaded here: Technical Specifications Hazcalc


Watch the tutorial below and see the Hazcalc User Manual.

Hydrogen applications can be assessed with Hazcalc, as well both for indoors and outdoor situations. Hydrogen applications, like compressors, tank facilities and pipe and ducting are mostly assessed as a normally closed and pressurized system.

Therefore under step 2 of the assessment, type of release, the "pressurized" assessment must be selected. In step 3 "release assessment", the possible release rate is automatically calculated, based on the differential pressure and the leak-size and other variables.

In step 4 the ventilation assessment has to be done. Typical for hydrogen, special attention is needed for assessing the background concentration, since the background concentration is an average concentration within the whole room under consideration. Hydrogen however, is very light and will move upward within a room and a ceiling layer can be formed. This can lead to a high concentration under the ceiling and this can create hazards.
So the background concentration, defined under the IEC 60079-10-1 standard, is not a good value to assess the dilution within a room. Another online tool must be used for assessing the possibility of ceiling formation. This can be done with HyRAM, a free online tool that can be used for, among other things, the assessment of layer formation under ceilings.


So with Hazcalc the hazardous area, due to a jet release and its size can be assessed and in addition to that, with HyRAM the formation of a ceiling layer can be assessed. These two assessments together give a good way of assessing hydrogen releases for indoor and outdoor situations which will result in a specific hazardous area.

Within the (future) hydrogen economy, specific and more detailed standards will be developed e.g. for electrolyzers and fuel cells. For more specific advice or help with hydrogen assessments, feel free to contact us.

All assessments made with Hazcalc can be downloaded / exported directly to a Micrisoft Excel formatted xlsx file.

The values of this file can be copy-paste to an Importmodule and an automated table can be extracted within a few clicks. This table can easily be modified.

The Importmodule can be downloaded here: Importmodule.xlsx

User manual

Yes, the user manual can be found here: Hazcalc User Manual