FAQ Categories: System Design

The main advantage of a “tee” style design is that the thrust loads at the vent exits are balanced. This means that an unequal force that might push the vent stack over is not present. Generally,…

The ASME BPV Code, and other Codes by reference, require less than back pressure of 10% of device set pressure from the release flowrate for proper operation of reclosing relief devices such as…

There are dozens of safety considerations for safe design of hydrogen vent stacks. Their primary function
is to vent the hydrogen safely, so vent stacks should be designed such that the gas…

The most common modes of failure for vent lines is backpressure and thrust forces.
Backpressure failures can be from several causes:

• Inadequate calculation of the backpressure caused…

Panel members have not encountered a device or area classification for ATEX approval within Canada. ATEX is a European Union directive and is not generally recognized within North American…

The end use of hydrogen usually drives the cleaning for initial construction. 

1. When the hydrogen is used for combustion and many industrial…

A release is defined by the amount of hydrogen, the rate of hydrogen flow, vent location (indoors or outdoors), geometry in the area (confined or not), and pressure. 

A small or large…

Low-pressure vents at mostly low hydrogen purity are not as large safety risk as high-pressure pure hydrogen vents. These vents should still go to a vent stack, but it will probably be small in…

It is best to avoid planned blowdown of large amounts of hydrogen inventory at high flowrates if possible.  Low flow releases from vent systems are normal and occur for purging,…

The distances provided are minimums. While they might be sufficient for most vents from small systems, larger vents will require both a dispersion and radiation analysis to determine the height…

Yes, there are differences due to the differences in the fluid properties. We’re not sure what is meant by blowdown. If this means that should the gases be vented to a vent stack, possibly, but…

Vent stacks and building ventilation systems are different and should be analyzed/designed differently. NFPA 2 has different location requirements for vent stack and ventilation system outlets.…

We are not certain what an inverted vent top is. If this means the hydrogen flow is pointed downward in any way towards grade, then yes it must be avoided. Less dangerous vent gases can be pointed…

TIA 1783 points out a valid concern about how to address the electrical classification zone around a liquid hydrogen system. The existing requirements specify 3' around the outlet of the stack for…

The vent system for the excess hydrogen should be vented in accordance with NFPA 2 and CGA G-5.4 and G-5.5. The oxygen also must be vented safely and should be in accordance with NFPA and CGA G-4.…

Cylinders are required to be tested periodically to verify structural integrity. The most common test method is hydrotesting, which means water is the most likely impurity that solidified in the…

Applicable EU Directives frequently include the following:

·        Low Voltage - 2014/35/EU

·        Machinery - 2006/42/EC

·  …

There are several concerns with “snuffing” a hydrogen fire from a vent stack. Most importantly, snuffing a hydrogen fire before the hydrogen is isolated…

The suitability of flame arrestors depends on the design of the system, but generally flame arrestors are
rarely needed for hydrogen systems when there is a 100% hydrogen atmosphere upstream of…

Flame arrestors can be installed on hydrogen gas vents. The purpose of a flame arrestor is to prevent the migration of flame backwards and upstream into the vent stack or system itself. Generally…