Classification |
Toxic, oxidizing agent, powerful disinfectant |
Molecular Formula |
O3 |
Molecular Weight |
47.997 g/mol |
Fire Hazard Rating
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- Risk of fire and explosion on contact with combustible substances
- May cause or intensify fire
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Explosion Range
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- Neither explosive nor flammable on its own
- Reacts explosively when shocked, exposed to heat or flame or by chemical reaction with organic substances/reducing agents
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Ozone
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- Pure ozone is a bluish colour, when mixed with air it is colourless
- Has a distinctive, pungent odour
- Has a half-life of 12 hours in air, 3 to 20 minutes in regular water, up to 2.5 hours in high quality, double ozonation/filtration water
- Pure ozone is heavier than air but it mixes completely with air and does not necessarily settle to the floor
- Very reactive gas and will corrode most metals and damage most plastics and cause rubber to go brittle and crack
- It is manufactured on site for immediate use because it is an unstable gas and decomposes quickly
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Toxic Effects of Ozone
NOTE: Long-term exposure to ozone will not help you develop a tolerance to it; the nose rapidly loses its ability to smell ozone.
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0.01 ppm Odour threshold
0.1 ppm May cause mild irritation of the eyes, nose, throat
0.10 - 0.25 ppm Headache, dry cough, some reduction in lung function in 2 - 5 hours
0.3 ppm Reduction in lung function during moderate work for all persons in 2 hours
0.6 ppm Chest pain in 2 hours
1 ppm Lung irritation , severe fatigue in 1 - 2 hours
10 ppm Severe pneumonia (arc welders) with intermittent exposure
11 ppm Rapid unconsciousness in 15 minutes
50 ppm Expected to be fatal in 30 minutes
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Exposure Limits of Ozone
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0.05 ppm Maximum allowable concentration averaged over an eight-hour period for heavy work
0.08 ppm Maximum allowable concentration averaged over an eight-hour period for moderate work
0.1 ppm Maximum allowable concentration averaged over an eight-hour period for light work
0.2 ppm Maximum allowable short-term exposure for less than or equal 2 hours
10 ppm Immediately dangerous to life and health (IDLH)
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Potential Causes of Leaks
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- Equipment that is not inspected regularly or replaced when necessary leading to equipment malfunction
- A destructor that isn’t working properly
- A pipeline blockage or clogged valve
- Worn or damaged pipes, tubing, gaskets or valves
- Using an incorrect material for joint sealers, pipes, valves, gaskets, diaphragms, tanks, sealants, etc.
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Ozone Generator Rooms
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NOTE: This is a general guideline. Follow local and appropriate codes/standards/regulations in your area to ensure proper compliance.
- Access should be restricted to authorized personnel only
Posted at the entrance to the room should be a warning sign that ozone is present
- Ventilation system with ability to provide required number of air changes for general ventilation and emergency ventilation
- An emergency electrical shut off switch to manually shut off the power to the ozone generator must be located outside the room
- Electrical switches controlling lighting and exhaust ventilation must be mounted outside the room
- Room must be equipped with emergency lighting
- Room with floor area larger than 40 m2 (430 f2) or longer than 10 m (33 ft) on any side, must have two exit doors to ensure accessible escape routes
- All exit doors must open outwards and must be fitted with panic hardware (a crash bar for easy exit) and not be self-locking
- All openings in ozone generator rooms (for example, in walls or ceilings) must be tightly sealed, including electrical conduits, access ports, monitoring apparatus, etc.
- Do not store chemicals, solvents or any combustible materials in the ozone room
- If the ozone generating system uses a pressure-fed ozone delivery system (compressor) to feed air into the generator, the room should not contain any auxiliary equipment
- If the ozone generating system uses a vacuum ozone delivery system (venturi), the room may contain other operating equipment (such as sand filters, furnaces and pumps)
- An ozone gas detection alarm system should be installed with an indicator located outside the room at each entrance
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Protection
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- Continuous ozone detection and alarm system for early detection
- Eye wash and shower facilities
- Accessible shutoff valves, pump lockout procedures
- Fully stocked first aid kits
- Personal protective equipment including an escape respirator
- All equipment should be protected against mechanical damage
- Ventilation system and emergency ventilation exhaust system
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Emergency Response Planning - steps to address an ozone leak
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- Provide training, instruction and supervision
- Write down safe work procedures
- Have an exposure control plan in place
- A written respiratory protection program that meets regulations
- Regular worksite inspections
- Legible and permanent identification on ozone generators and WHMIS workplace label required
- After maintenance work and before operation, system must be appropriately vacuum tested or pressure tested to detect leaks
- Have a maintenance schedule that outlines daily, weekly, monthly and annual inspections, testing, replacing and servicing equipment
- Have breathing apparatus and protective clothing close by
- Have emergency and evacuation procedures written down
- Conduct scheduled emergency drills
- Have procedure on how to notify emergency response units and adjacent worksites/homes
- Conduct a formal investigate any time enough ozone is released to set off the alarm
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Ozone Gas Detection System
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- 24 hour continuous monitoring with an alarm response if ozone concentrations reach a certain pre-set level (at or below 0.1 ppm)
- In alarm circumstances, the gas detection system should shut off the ozone generator and activate the emergency ventilation system (exhaust vents should be located well away from frequented areas)
- The gas detector must be located beside the equipment and between the generator and the destructor; reaction tanks or destructors more than 5 m (16 ft) apart need their own gas detector
- The ozone concentration in the exhaust air stream should be monitored regularly either with a gas detector or a detector tube
- Tested at least on a monthly basis and calibrated at least annually by qualified personnel
- Must have direct readout of the current gas level that can be seen from outside the room (at all entrances)
- Audible and visual alarms should be located outside all entrances to the room and at another separate location in the building
- Other gas monitoring devices such as detector tubes, test papers and air flow meters should be used in addition to a fixed gas detection system
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