Basic Nitrogen Safety Course San Juan College Regional Energy Training Center

Understand Hazards Associated with Nitrogen  Your Safety  Safety of Others  Recognize Hazards  Take Corrective Action  Respect N2

Physical Properties of Nitrogen  Boiling Point is Fahrenheit  Liquid Density is pounds per gallon  Heat required to convert liquid to 70 F Gas is 184 btu per pound  Expansion Ratio of liquid to Gas is 697 to 1 One gallon of Liquid Nitrogen at F is equal to scf/70 F Gas

Nitrogen in Air  Air contains 78% nitrogen, 21% oxygen and 1% other rare gases  Nitrogen Gas is: Colorless Odorless Non-toxic or irritating Does NOT burn or support combustion Will NOT support life functions A poor conductor of heat  Oxygen supports combustion and life support  Oxygen equals 21% of the air you breath

The Cryogenic Thermometer Shows extraordinarily cold nature of liquid nitrogen  Oxygen F  Carbon Dioxide F  Nitrogen F  Absolute zero F  Water +212 F Liquids can boil on the positive and negative side of the temperature spectrum

Avoid Skin Contact  Avoid touching or exposing skin to: Liquid Leaking from Equipment  Destroys tissue similar to high temp burn Cold Equipment surfaces Freeze Burns  PPE should be worn

Safety Precautions for handling Liquid Nitrogen  Wear Protective Clothing at all times when working with nitrogen  Never work around nitrogen without: Hard hat Safety glasses or safety goggles and a face shield Loose fitting insulated gloves Long sleeve shirts Cuff-less trousers (worn outside of safety boots) Hearing protection Safety boots

Protect Your Eyes  Liquid nitrogen causes immediate damage  EYE DAMAGE IS USUALLY BEYOND REPAIR  One drop liquid nitrogen to the eyeball could damage the eyeball instantaneously One second of unsafe practice you could be blind for LIFE!

Acceptable Cryogenic Materials  Copper and brass  Stainless steel of the 300 series and  Aluminum (open ended only – low PSI) EXAMPLES OF CRYOGENIC COMPONENTS Inner tank of a nitrogen tank Nitrogen low pressure piping Nitrogen fluid ends Nitrogen high pressure piping

Non-Cryogenic Material  Examples of Non-cryogenic material: Carbon steels – which becomes brittle at -40 F Low alloy steels Most Rubbers Most plastics

Non-Cryogenic Components  Examples of Non-cryogenic components: Treating iron – made of carbon steel (liquid nitrogen should never be allowed to enter or flow through it) Cryogenic tank casing and other components will crack when liquid nitrogen lands on the surface as these are made from carbon steel (ex: when overfilling occurs)

Non-Cryogenic Components Examples of Non-cryogenic (continued) Trailer frames Power trains Structural components Hydraulic lines Tires

Treating Iron will NOT withstand Cryogenic Temperatures  Allowing liquid nitrogen in the carbon steel treating iron is one of the most dangerous mistakes – shock could cause treating iron to break like glass  Carbon steel cannot withstand rapid contraction  Treating iron must not be hit or moved while frozen

Liquid Air Hazard  Ambient air condenses on the cold surface with -320 F liquid nitrogen in the pipe  Boiling point of nitrogen is lower that the boiling point of oxygen  Condensed liquid air can result in puddles containing approximately 52% oxygen  Oxygen-enriched air may cause non- combustible material to become flammable and normally flammable material to burn a a highly increased rate

Nitrogen Expansion  Nitrogen expands 697 times it’s volume in going from a liquid at -320 F to 70 F

Effect of Trapping Liquid Nitrogen  Liquid nitrogen has a 697 to 1 expansion ratio  It is important to note the pressure difference with temperature increase, in a closed container

Effect of Trapping Liquid Nitrogen  Trapped liquid nitrogen will absorb heat and can exert pressure in excess of 21 tons per square inch  Any place nitrogen can be trapped, a rego safety or popoff is used

 12 FEET OF 3’ TREATING IRON FULL OF NITROGEN AT 10,000 PSI HAS THE SAME ENERGY AS 90 POUNDS OF NITROGLYCERIN

Symptoms of Oxygen Deficiency  Cold nitrogen gas will displace warmer air containing vital oxygen for breating in a confined space  You need 21% oxygen for normal breathing and life support

Symptoms of Oxygen Deficiency (continued)  Oxygen is necessary for us to live and function.  Slight oxygen deficiency results in: deeper respiration Faster pulse Poor coordination

Symptoms of Oxygen Deficiency (continued)  As Oxygen deficiency INCREASES: Ones judgment becomes poor  He may or may not know to move to a well ventilated area

REMEMBER  NITROGEN WILL DISPLACE OXYGEN WITHOUT WARNING _________________________ Maintain proper ventilation to prevent asphyxiation

REMEMBER  One full breath of pure nitrogen will strip blood of necessary oxygen resulting in a loss of consciousness

REMEMBER  Always be cautious when there is a nitrogen gas cloud present.  Never enter a gas cloud unless you are certain that it is NOT oxygen deficient  If you suspect an oxygen deficient atmosphere – use company Confined Space Entry procedures and use appropriate breathing apparatus before entering