Refineries and large petrochemical plants will frequently have flare systems for H2 and other flammable materials. One of the major purposes of these flare systems is to prevent a large unignited cloud from forming since that could result in an explosion hazard and large deflagration overpressures if there is a delayed ignition. However, these are in large facilities which have the infrastructure to support flare operations. ,

API 521 is the only standard with which the Panel is familiar that addresses flaring. This document provides good guidance. The reactivity and flammability dissuade flaring when the flaring poses more hazards than benefits, as stated in API 521 (Section 5.2.1), which can be argued is the case with hydrogen for typical industrial gas applications.

Flares are very rarely used at user locations downstream of the production plants.  Releases, either operational or emergency, tend to be smaller at these facilities. Flowrates also tend to be highly intermittent which raises the risk of flame blowout and reignition. The capital and operating cost can also be relatively high and there may also not be the utilities required to support a flare system. Another consideration is that in many jurisdictions, an air permit is required to address potential air pollution regulations, particularly with regard to NOx.  

There are situations where a flare could be advisable, particularly if a vent system is installed in a process where there could be large releases.  However, a better approach might be to address the source of the release and attempt to mitigate that in some other way. The effectiveness and need should be evaluated through a risk assessment.

There are companies that specialize in flare systems. The HSP is not in a position to comment about specific products and potential applications should be discussed and validated with those manufacturers.