To check gas release in an atmosphere can generate flammable mixture concentration (between LFL & UFL)

Purpose of Study             :              To find whether gas release in an atmosphere can generate flammable mixture concentration (between LFL & UFL)

Location                             :              Cylinder storage area 

As we aware that the Flammable Range (Explosive Range) is the concentration range of a gas or vapor that will burn (or explode) if an ignition source is introduced.

Three basic requirements must be met for explosion to take place:

1. Fuel
2. oxygen or air
3. source of ignition

Below the explosive or flammable range, the mixture is too lean to burn and above the upper explosive or flammable limit the mixture is too rich to burn. The limits are commonly called the "Lower Explosive or Flammable Limit" (LEL/LFL) and the "Upper Explosive or Flammable Limit" (UEL/UFL).

From this study we can find out whether a gas release in an atmosphere can generate flammable mixture concentration (between LFL & UFL)

Assumption:

Volume of the room                      =             40.77 Cu.m

Gas                                                     =             Acetylene

Weight of acetylene in cylinder   =             5 kg

Air exchange rate in the room     =             Very little

Calculation:

Density of air at 30°C                     =             1.1644 kg/Cu.m

Mass of air in the room                 =             40.77 * 1.1644                  = 47.47259 kg

Molecular weight of air                 =             29

So, Number of kg-moles of air     =             47.47259 /29                    = 1.6369

Number of kg-moles that would add if leaked from the cylinder is

= 5 (weight of acetylene in cylinder)/26.04 (molecular weight of acetylene)           = .192

% of acetylene in air (after acetylene release is)  =             (.193/1.6369)*100          

= 11.72% (The Flammability limit of acetylene is from 2.5(LFL) to 81(UFL) %).

Conclusion :

·        If 5 kg of acetylene is released from cylinder in that storage room atmosphere the concentration of flammable gas mixture in atmosphere will become as 11.72% & if any source of ignition present at time leads to explosion.

Recommendation:

·        LFL detectors to be kept & its monitoring is to be linked with BMS (building Management System).

·        Less capacity storage cylinders availability needs to be checked.

·        Hose & pipeline (rigid & flexible) should be Weekly.

·        Flame proof fittings to be provided & electrical switches need to be kept outside of the room.

·        If alternate method used for hydrogen generation then cylinders can be kept outside the building & in well-ventilated area.