IG-55
Effective fire protection with zero environmental impact with an IG-55 extinguishing system
Overview.
Effective fire protection with zero environmental impact with an IG-55 extinguishing system
Both Argon and Nitrogen are clean, naturally occurring gases that are readily available throughout the world. The system has no direct global warming or ozone depletion potential. IG-55 requires minimal post-fire clean up and will not decompose or produce any by-products when exposed to a flame from a fire situation.
IG-55 systems are engineered for total flooding of an enclosed space. It extinguishes a fire by means of reducing the oxygen content within a room to the point at which fire can no longer burn, but without compromising the safety of individuals present.
IG-55 is safe and effective for use on many applications. It is well suited for leaky enclosures such as flight simulators, substations, and control rooms and for application with multiple hazards.
Trade Names.
Argonite, Argogen, Inertech IG55, I-Flow IG55, Proinert IG55
Chemical Composition.
IG‑55 is a colourless, odourless, electrically non‑conductive gas with a density approximately the same as that of air. It is an inert gas mixture consisting nominally of 50% argon and 50% nitrogen.
Gas Specification.
The gas specification is usually confirmed with a certificate of conformity (COC) from the manufacturer. It’s also important to ensure each specification is maintained during the 10-year testing and a new COC is provided confirming each requirement below by your supplier for the new re-filled or re-tested agent.
The mixture specification for IG-55 is as follows:
a) argon percentage range (50 ± 5) %
b) nitrogen percentage (50 ± 5) %
Extinguishant IG-55 shall comply with the specification shown below:
| Component | Argon | Nitrogen |
|---|---|---|
| Purity | > 99,9 % | > 99,9 % |
| Moisture | < 15 parts per million | < 10 parts per million |
Physical Properties.
| Property | Units | Value |
|---|---|---|
| Molecular mass | n/a | 33.98 |
| Boiling point at 1,013 bar (absolute) | °C | - |
| Freezing point | °C | - |
| Critical temperature | °C | - |
| Critical pressure | bar | - |
| Critical volume | cm3/mol | - |
| Critical density | kg/m3 | - |
| Vapour pressure 20 °C | bar abs | - |
| Liquid density 20 °C | g/ml | - |
| Saturated vapour density 20 °C | kg/m3 | - |
| Specific volume of superheated vapour at 1,013 bar and 20 °C | m3/kg | 0.708 |
Design Concentrations.
| Standard | Class A | Higher Hazard Class A / Class C | Class B |
|---|---|---|---|
| (BS) EN 15004 | 40.3% | 45.2% | 47.6% |
| NFPA 2001 | 37.9% | 42.7% | 45.5% (n-heptane) |
| APSAD | 40.3% | 45.1% | Subject to hazard |
| ISO 14520 | 41.1% | 45.1% | 47.5% |
| LPCB | 38.9% | 44.2% | 45.9% |
| FM 5600 | 38.8% | 43.6% | 39.7% |
| UL 2127 | 38.8% | 43.6% | 39.7% |
Loael, Noael & Minimum Safety Precautions.
The below is based on the requirements of EN 15004 which is the most common design standard in the UK and other European areas.
| Property | Value |
|---|---|
| No observed adverse effect level (NOAEL) | 43.0% |
| Lowest observed adverse effect level (LOAEL) | 52.0% |
| Concentration | Time delay device* | Automatic / Manual Switch** | Lock-off device*** |
|---|---|---|---|
| Up to and including the NOAEL | Required | Not Required | Not Required |
| Above the NOAEL and up to the LOAEL | Required | Required | Not Required |
| LOAEL and above | Required | Required | Not Required |
* Time delays are usually integrated within the main gas extinguishing panel to allow a 30 second delay before the system discharges. Hold off buttons are also usually located adjacent the exits of the enclosure.
** Automatic / Manual switches are usually integrated into the main gas extinguishing panel located at the entrance of the protected area.
*** Lock-Off devices are usually manual isolation valves installed within the pipework and again located at the entrance of the protected area.
IG-55 Quantity Calculation.
Typically, gaseous extinguishing systems are used for protecting electronic equipment in data rooms or similar, we have therefore prepared a quick calculation to help understand and estimate the quantity IG-55 agent required in your enclosure. The factor provided below is also based on a design temperature of 20°C and an altitude of 0, changes in either will have a small effect on the agent quantity
Design Concentration = 45.2% (Higher Hazard Class A)
Flooding Factor = 0.8494
Volume of enclosure in M³ x Flooding Factor = Quantity required in KG
[Example assuming room volume of 150m³]
150 x 0.8253 = 127.411kg
For a calculation spreadsheet in excel format or for quantity calculations outside of these parameters, please contact us directly at
hello@mepfire.com.
Typical Cylinder Fill Weights, Sizes, Pressures & Quantity Calculator.
Inert gas cylinders come in a range of sizes however the below is reflective of the most common sizes and pressures and corresponding fill weights for reference.
| Pressure | 67 Litres | 80 Litres | 140 Litres |
|---|---|---|---|
| 200 bar | 19.3kg | 23.0kg | 40.3kg |
| 300 bar | - | 32.2kg | 56.4kg |
By using the quantity calculation above, and the maximum fill of each cylinder above, you can work out how many cylinders are typically required for your protected area.
Environmental Considerations.
Extinguishant IG‑55 is an inert gas and has zero GWP and zero ODP.
Temperature Vs Pressure Graphics
Temperature graphs are useful for verifying the pressure or your cylinders and whether they need replacing in line with the recommendations of BS EN 15004 which advises:
- Non-liquefied gases: for inert gas agents, pressure is an indication of agent quantity. If a container shows a loss of agent quantity or a loss of pressure (adjusted for temperature) of more than 5%, it shall be refilled or replaced.
Pressure vs. temperature for IG-55 pressurised to 150, 200 and 300 bar at 15°C