1 HVACR416 – Design Two Types of Accidents

2 Mechanical malfunction or human error Electrical causes Excessively high pressures Burns and scalds Explosions Inhalation of toxic and non-toxic gases Mechanical malfunction or human error Electrical causes Excessively high pressures Burns and scalds Explosions Inhalation of toxic and non-toxic gases Accidents – Causes & Nature

3 Broken limbs Thrown objects Smashed fingers, toes, etc. Falls Eye injuries and cuts Broken limbs Thrown objects Smashed fingers, toes, etc. Falls Eye injuries and cuts Injuries from Mechanical Causes

4 Electrical Injuries Three types of electrical hazards – Shock – Burns – Blast Three types of electrical hazards – Shock – Burns – Blast

5 Current in milliamperesEffect on the human body Less than 0.5 mANo sensation 2 to 10 mAMuscles contract 5 to 25 mAPainful shock, inability to let go Over 25 mAViolent muscle contractions 50 to 100 mAHeart convulsions (ventricular fibrillation), possible death Over 100 mAHeart paralysis, inability to breathe, burns, almost certain death Effect of Electric Shock

6 High Pressure Injuries Mechanical refrigeration uses pressures above atmospheric pressure – Must be contained – Vessels must not burst – Pressures change with temperature Mechanical refrigeration uses pressures above atmospheric pressure – Must be contained – Vessels must not burst – Pressures change with temperature

7 Pressure Containing Vessels Designed for “normal” pressures – If overheated may “give” somewhat – When limit of elasticity is reached, will burst Large parts may be blown out If bulge is noticed, relieve pressure immediately Designed for “normal” pressures – If overheated may “give” somewhat – When limit of elasticity is reached, will burst Large parts may be blown out If bulge is noticed, relieve pressure immediately

8 Ignition Sources Flammable refrigerants, gases, solvents, and fuel oil Steam, hot oil or hot water Hot pipes or un- insulated parts Chemical burns Burns and Scalds Fire hazards include:

9 Explosion Injuries Explosion and flammability are related Confined vapor seeks more room – Pushes outward with tremendous force “Explosion” Difference in catching fire vs. exploding – Exploding includes violent force Explosion and flammability are related Confined vapor seeks more room – Pushes outward with tremendous force “Explosion” Difference in catching fire vs. exploding – Exploding includes violent force

10 Toxic Gases Toxic = poisonous Refrigerants and other gases vary in toxicity – Ammonia and sulfur dioxide are highly toxic Harmful effects are based on – Nature of gas – Concentration – Length of time breathed Toxic = poisonous Refrigerants and other gases vary in toxicity – Ammonia and sulfur dioxide are highly toxic Harmful effects are based on – Nature of gas – Concentration – Length of time breathed

11 Radiation Accidents Radiation types – Ionizing X-rays – Non-ionizing Alignment lasers Welding produces ultraviolet light – Eye and skin hazard Radiation types – Ionizing X-rays – Non-ionizing Alignment lasers Welding produces ultraviolet light – Eye and skin hazard

12 Heat and Cold Injuries Avoid extreme heat and cold Obvious dangers – Heat stroke – Hypothermia – Frostbite Other problems – Fatigue, discomfort, etc. Avoid extreme heat and cold Obvious dangers – Heat stroke – Hypothermia – Frostbite Other problems – Fatigue, discomfort, etc.

13 Cold Weather Danger: Hypothermia Hypothermia – Shivering – Loss of consciousness – Decreasing pulse and breathing If symptoms are shown – Call emergency services – Move to warm area Dress in layers Hypothermia – Shivering – Loss of consciousness – Decreasing pulse and breathing If symptoms are shown – Call emergency services – Move to warm area Dress in layers

14 Cold Weather Danger: Frostbite Ice crystals on body tissue – Ears, nose, chin, fingers, toes Skin color changes – Flushed, white or grayish yellow, then grayish blue Ice crystals on body tissue – Ears, nose, chin, fingers, toes Skin color changes – Flushed, white or grayish yellow, then grayish blue

15 Cold Weather Danger: Frostbite Signs shown? – Move to warm area, use warm water, call health care provider Prevention – Cover extremities – Move to warm area if pain is evident Signs shown? – Move to warm area, use warm water, call health care provider Prevention – Cover extremities – Move to warm area if pain is evident

16 Accident Reporting All must be reported without delay Follow these steps – Report to supervisor immediately – Employer keeps record of accident – Current codes are reviewed – Leave the site intact All must be reported without delay Follow these steps – Report to supervisor immediately – Employer keeps record of accident – Current codes are reviewed – Leave the site intact

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