Directors Forward – As a company we try to avoid using extinguishants such as FM200 or Novec (unless specifically requested by the customer) as they don’t fit in with our environmental policy. Also the inert gas systems are much safer as they do not contain chemicals.

What is a Fire Suppression System?

Suppress – To forcibly put an end to.

A Fire Suppression System works by forcing out highly oxygenated air with a blend of non-harmful gasses to remove a fires primary fuel source therefore eliminating the fire.

The air we breathe has approximately 21% of Oxygen which is the key factor in sustaining a fire and also in keeping us alive. By removing the Oxygen the fire will be extinguished but that comes with an obvious problem. How can we sustain life at the same time?

Fires need more than 15% Oxygen to combust so anything below this will not be enough for a fire to sustain itself. Luckily, humans only need 12% of oxygen to survive and this is where the answer lies. To extinguish a fire and sustain life, we need to reduce oxygen from 21% to below 15%, but not less than 12%. This will extinguish a fire and sustain life at the same time.

But what happens if oxygen levels go below 12% and someone is inside?

If the oxygen level goes below 12% and above 10% you will start to feel the effects of NOEAL (No-Observed-Adverse-Effect Level) this will cause these symptoms:

Fire Suppression System Cylinders

Shortness of breath - This is a dangerous, by reducing oxygen to below 12% you can cause all sorts of problems to your respiratory system. You would experience shortness of breath as your blood oxygen saturation falls, this will become worse over time and will affect you even when you are resting.

Fatigue - You will begin to experience fatigue, feeling far more tired than normal, possibly feeling exhausted.

Cognitive Disturbance - When your bodies are starved of oxygen, you may begin to experience confusion, uncertainty and disorientation.

Headaches - Headaches will become apparent as your brains are starved from this essential element of the air we breathe.If the oxygen levels drop even further than 10%, then the symptoms become far more severe, often with life threatening circumstances this is known as LOEAL (Lowest-Observed-Adverse-Effect Level).

The Design

Well-designed fire suppression systems must be constructed on essential design principles, this is why our extinguishing systems are engineered with the following considerations:

Cylinder storage space requirements:

  • Room Infrastructure, ensuring the enclosure is suitable for the fire suppression agent
  • Safety to occupants, using our BAFE SP203 Part 3 and BSI certified quality management procedures
  • Environmentally friendly systems; correct designs prevent unnecessarily system discharges
  • Accurate and reliable smoke detection using the VESDA air sampling technology
  • Sustainable fire suppression technology, ensuring users are well informed about what they are installing

Argonite (IG55) v Inergen (IG541)

  • N₂ - 50%
  • AR – 50%
  • N₂ - 50%
  • AR – 40%
  • CO₂ - 8%
CO₂ Impact:
  • Simple mixture & commonly available from gas suppliers
  • Doesn’t contain CO₂ therefore not impacted by CO₂’s affect.
  • Artificially increases breathing, increasing the intake of toxic gases
  • Patentable formula reducing number of refill suppliers
  • Inexact fill percentages can create dangerous condition if too much CO₂ is used
  • According to NFPA 2001, IG-55 and IG-541 have the same NOAEL/LOAEL and exposure limitations. No added benefit from the addition of CO₂.
System Details:
  • Each Cylinder is mounted with an accurate pressure gauge with a supervisory pressure switch
  • The Argonite system has a 1:100 primary to slave cylinder ratio
  • All cylinders are pneumatically connected to each other.
  • Inergen uses a gauge that cannot reliably be used to establish fill pressure or used to safely detect pressure loss
  • The system has a 1:40 primary to slave cylinder ratio
  • Inergen uses backpressure to actuate slave cylinders. This method is not as reliable, especially for larger systems.

INFINITI’s Chosen Method & Summary

At INFINITI we prefer IG55 due to the lack of CO₂ as it is safer for the environment. CO₂ also increases the rate you breathe which means you will intake the air with less oxygen more frequently, speeding up the negative effects of lack of Oxygen to the body. Also as IG55 is a simpler formula it is much easier to get from suppliers and slightly more cost effective.

For more information or a quote on Fire Suppression Systems from INFINITI
email or call us on 01993 774444.