Saturday, May 30, 2015
Oxygen and Nitrogen cylinders typically have 2500 psig pressure
Oxygen is one of the three elements of the Fire Triangle (Fuel, Oxygen, Heat/Spark)
Oxygen cylinders are usually green in color
Nitrogen cylinders are usually black in color
Acetylene cylinders typically have 250 psig pressure
Acetylene is a highly explosive fuel gas used for brazing and welding
Acetylene burns at over 3,000 C/6,000 F (one of the hottest burning fuel gas)
Acetylene cylinders are usually maroon in color
Acetylene chemical formula is C2H2
Pressure relief valve set at 400 psig
ACETYLENE CYLINDER PROJECTILE FORCE
Example: 6 x 20 inch --- small cylinder
Diameter = 6 inch
Radius = 3 inch
Height = 20 inch
Cylinder pressure = 250 psig
Weight = 22 lbs
Capacity = 40 cubic foot of acetylene gas (120 times compressed vs. empty)
Capacity of cylinder without gas = (pi/4) x D^2 x H
Capacity of cylinder without gas = (pi/4) x 6 in^2 x 20 in x 1 cubic foot/1728 cubic in
Capacity of cylinder without gas = 0.33 cubic feet (empty)
Full capacity comparison = 40 cu ft/0.33 cu ft = 120 times compressed
Cylinder Total Surface Area, TSA
TSA = 2 x pi x r x h + 2 x pi x r^2
TSA = pi x d x h + 2 x (pi/4) x d^2
TSA = pi x 6 x 20 + 2 x (pi/4) x 6^2
TSA = 377 + 57
TSA = 434 sq. in.
Total Cylinder Projectile Force = Pressure x Area + Cylinder Weight
Total Cylinder Projectile Force = 250 lb/sq in x TSA + 22 lbs
Total Cylinder Projectile Force = ( 250 x 434 ) + 22 lbs
Total Cylinder Projectile Force = 108,500 lbs + 22 lbs
Total Cylinder Projectile Force = 108,522 lbs
Total Cylinder Projectile Force = 54 tons approx.
*** Small pressurized cylinder with huge 50 ton force projectile !!!
PRESSURIZED CYLINDERS (PRESSURE VESSELS) SAFETY
1. Before working with pressurized cylinders, check them first.
2. Check valves, regulators - broken, damage, leak.
3. Check hoses - wear, crack, leak, damage.
4. Pay attention to leaks, noises and unusual smell.
5. After checking, if you found any defects, don't use it.
6. Keep cylinders a distance away from the work area --- don't braze/weld directly in front of the cylinder!
7. Always wear personal protective equipment when working with pressurized cylinders.
8. Open quarter turn only, this is enough for most jobs, faster to close in case of emergency.
9. Know location of fire extinguishers and nearest exits when working with pressure vessels.
1. Don't drop - damages valves, etc.
2. Transport in upright position.
3. When transporting heavy cylinders, they must have a safety cap securely fastened and be in an approved cart with chains to secure the cylinders.
1. Store in upright position and ensure safety cap in place - to prevent tripping, valve damage, etc.
2. They must have chains to prevent from falling over.
3. Oxygen and Fuel cylinders must be separated with a minimum wall height of 5 ft or 20 ft distance away from flammable substances such as paint.
CYLINDER SAFETY DEVICES
1. Pressure relief valves
2. Fusible plugs (low melting point)
3. Pressure regulators
4. Safety cap
If you find a leaking cylinder, use your discretion, safety first!!!
If the leak is small and it is safe to close the valve, then immediately close the valve without endangering yourself.
If the leak is big, evacuate the area, close the door, pull the nearest fire pull station to sound the alarm, call Fire dept...