Saturday, July 13, 2019

Which Gas Fire Suppression System is best? - FM200, Novec 1230 or Inergen?

Which Gas Fire Suppression System is best? - FM200, Novec 1230 or Inergen?

April 10, 2017

So, you have to choose a gas fire suppression system to protect against fire destroying valuable assets such as Computer Equipment, Document Vaults or Telecommuncations / Switch Gear. You have a choice between Chemical Fire Suppression Systems such as Novec 1230 or FM200 and Inert FIre Suppression Systems such as Inergen.


Is there a clear cut choice when it comes to Gas Fire Suppression? 

Well, no is the answer, but there are clear reasons to choose one over the other depending on the hazard size and location.

We will consider:
  • Environment
  • Safety
  • Speed of action
  • Storage Space
  • Cost

Environmental Considerations for Gas Fire Suppression Systems

This may not seem like an obvious first consideration when choosing a fire suppression agent, however there is some method to my madness. Read on to see why.

FM200 Fire Suppression

Firstly, FM200 is a HFC Gas that is now monitored under the Kyoto Protocal. Why? Well, it has a high Global Warming Potential and therefore has to be treated and monitored accordingly.
Any engineer working on an FM200 fire suppression system, even for maintenance purposes, has to be trained and certified in F-Gases.
The disposal of FM200 can only be carried out by licenced companies. All this additional licencing puts additional responsibilities and expense on the end user, who are often not aware of their repsonsibilities around this gas. 

So why is FM200 still chosen as a fire suppression agent? FM200 is more cost effective when its maintenance and disposal costs are left out of the equation. However, if the cost of the system is considered over its lifetime and subsequent disposal, then the obvious decision is to consider a different agent.



Novec 1230 Fire Suppression

Novec 1230 fire suppression agent is a relatively recent addition to the fire suppression industry. Manufactured by 3M, Novec 1230 comes with a 20 year "Blue Sky Warranty", guaranteeing its "Green" credentials. 
Choosing Novec 1230 over FM200 is the smarter choice and from here in this article, we shall consider only Novec 1230 and Inergen for that reason.

INERGEN 

INERGEN fire suppression agent is a mixture of three naturally occurring gases: nitrogen, argon and carbon dioxide. As INERGEN agent is derived from gases present in the earth’s atmosphere, it exhibits no ozone depleting potential, does not contribute to global warming, nor does it contribute unique chemical species with extended atmospheric lifetimes. Because INERGEN agent is composed of atmospheric gases, it does not pose the problems of toxicity associated with some of the chemically derived agents. 

So that is clear cut. Inergen is the cleanest of the fire suppression agents then. But wait......There is a far higher volume of Inergen required to cover the same hazard as Novec 1230 and it is stored at far higher pressures than Novec 1230. 

Inergen requires more steel to make the high-pressured steel cylinders for its storage. Therefore Inergen requires more energy for its manufacture, storage and transportation when compared to Novec 1230 systems.

Perhaps not as clear as it might first appear. However as far as the agent itself goes, Inergen is clean and therefore we will consider it further.



Environmental Winner? Inergen and Novec 1230 remain as sound choices.


Safety Considerations

Human Safety

When considering the safety of people that may be inside the hazard area, we shall look at the safety margin at the concentration levels of gas under the EN15004 Fixed Fire Suppression Standard.

Novec 1230 Fire Suppression Agent

For Surface Class A hazards, the concentration level for Novec 1230 required under EN15004 is 5.3%. The concentraiton level for Novec 1230, above which adverse effects can be observed in humans is 10%.

Safety margin = 88.7%

INERGEN Fire Suppression Agent

For Surface Class A hazards, the concentration level for INERGEN required under EN15004 is 39.9%. The concentraiton level for INERGEN, above which adverse effects can be observed in humans is 43%.

Safety margin = 7.7%


Operating and Storage Pressure

Novec 1230
25 Bar

Inergen
200 - 300 Bar

The amount of pressure relief venting required to ensure there is no damage to property in the event of a discharge will of course be higher with Inergen than Novec 1230.

Higher pipe pressures in the event of a discharge and cylinder storage pressures should also be considered in occupied environments such as office comms rooms or document vaults.
While cylinders are securely fastened to anchor points, inevitably fire suppression cylinders are removed and replaced in the event of discharge and when pressure testing is required.


Safest System for Humans and Property? Novec 1230



Speed of action

Novec 1230

Novec 1230 system are designed to fully discharge in 10 seconds. They act on fire by removing heat quickly, thus extinguishing the fire.

INERGEN

INERGEN systems are designed to discharge fully in 60 seconds. They act on fire by reducing the oxygen levels in the hazard enclosure, starving fire of one of its essential ingredients.

Fastest Agent? Novec 1230


Storage Space

The simple graphic below details the storage space required for each system under discussion.

The graphic below is based on the cylidner requirements for a 200m3 Class A Hazard


Winner based on Footprint? Novec 1230


Cost Factors

So far it seems that Novec 1230 is the obvious choice when it comes to the Environment, Human safety, Speed of action and Storage Space.

Why would any consultant or end user decide that INERGEN was the better choice over Novec 1230?

Answer: As the Hazard size increases, INERGEN starts to become more attractive from a cost perspective. In addition, it is possible to cover multiple hazards from one cylinder bank. 

INERGEN Cylinders can be stored at a far greater distance from the hazard than Novec 1230. 

Most Cost Effective System? Depends on Hazard Size and number of hazards in one location.

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