Inert Gas

With today’s world constantly pushing towards ‘Green’, Inert gases are an excellent choice for today’s fire suppression systems. These agents are based on naturally occurring gases found all around us – even in the air, that we breathe.

They are a class of gases which do not undergo chemical reactions under a set of given conditions, nor typically, do they react with many other substances.

What is an Inert Gaseous (continued)

The two most common Inert gases used as suppression system agents, either on their own or as part of a blended mix, are Argon and Nitrogen, and the most readily available agents utilising these two gases on today’s market are:

IG-01 – Argon
IG-55 – Argonite: A 50/50 blend of Argon and Nitrogen
IG-541 – 52% Nitrogen, 40% Argon & 8% CO2

Although CO² (Carbon Dioxide) is also used as a suppression agent in its own right, it has become unpopular over the years due to its adverse effect on the environment, and the potentially high risk presented to those in the immediate vicinity during a discharge (CO², under the right conditions, can be lethal).

Inert gas systems consist of a pre-defined number of cylinders (typically 80L in size, although other sizes exist) that are pressurized between 150 and 300bar, depending on the system design requirements. They can be a simple set-up, from 1 or 2 cylinders placed within a small Server room, all the way up to complex multi-diverter valve systems with dozens of cylinders, and pilot cylinders, covering a large Data Centre.

Pros & Cons of Inert Gaseous

Inert agents have their own ‘Pros’ and ‘Cons’. The agent itself tends to be more cost-effective than its synthetic gas counterpart and not as strictly regulated, unlike synthetic gases that also fall under the control of Fluorinated Greenhouse Gases (F-Gas) Regulations.

However, the footprint required to house Inert systems can be much larger than synthetic gas systems as generally, more cylinders are required for the volume being protected. Inert gas suppression systems also need to take over-pressure venting into consideration and vents must be fitted within protected areas to relieve access ‘positive’ pressure.

Inert gas systems extinguish a fire by lowering Oxygen levels (which are typically around the 21% mark) within a protected area, but within ‘safe for life support’ limitations. Typically, the Oxygen level is reduced to between 12%-14%, as fire requires an Oxygen level of 15% or above for combustion. Humans can survive on only 12% Oxygen in the atmosphere, so the calculations on agent design concentrations are crucial when deploying systems.

As with all ‘total flood’ gaseous suppression systems, an annual Room Integrity Test must be conducted to confirm the integrity of the protected area and the retention time.

All of Cannon Fire’s Inert agent suppression systems are designed, installed, commissioned and maintained under the requirements of BS EN 15004-1:2008, and the relevant sub-regulation particular to the agent being utilised, & BS 5306-4. Cannon Fire are also BAFE SP203-3 Registered.