1. Basic Ventilation PPT-040-01 1 Bureau of Workers’ Compensation
PA Training for Health & Safety (PATHS)
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2. Course Goals To understand the basic concept of ventilation
To understand reasons for ventilation
To understand and apply proper ventilation techniques
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3. Student Objective Be able to define what ventilation is
Be able to apply ventilation to different applications
Be able to determine best method of ventilation
Be able to move air
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4. Ventilation
The process of "changing” or replacing air in any space to provide high quality indoor air
To:
Remove unpleasant smells and moisture
Introduce outside air
Improve circulation, etc.
In firefighting, refers to a tactic of creating a draft to control the release of heat and smoke
Ventilating (the V in HVAC) is the process of "changing" or replacing air in any space to provide high indoor air quality (i.e. to control temperature, replenish oxygen, or remove moisture, odors, smoke, heat, dust, airborne bacteria, and carbon dioxide). Ventilation is used to remove unpleasant smells and excessive moisture, introduce outside air, to keep interior building air circulating, and to prevent stagnation of the interior air.
Ventilation includes both the exchange of air to the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/forced and natural types.[1]
In firefighting, ventilation refers to the tactic of creating a draft with an opening above or opposite the entry point so that heat and smoke will be released, permitting the firefighters to find and attack the fire. If a large fire is not properly ventilated, not only will it be much harder to fight, but it could also build up enough poorly burned smoke to create a smoke explosion, or enough heat to create a flashover. Contrarily, poorly placed or timed ventilation may increase the fire's air supply, causing it to grow and spread rapidly.
Mechanical fans can be used for such ventilation tactics, as can existing openings such as windows, skylights or heat/smoke vents on the roof. If there is no suitable existing hole, firefighters may use their equipment to make one, such as specialised saws for cutting a large hole in the roof. A conical hose-stream aimed around an opening -of a window or door, etc.- entrains smoke and thus increases the exhaust rate of smoke from the space. This is a process called "hydraulic ventilation". This strategy might be used when the fire is small and protecting property from smoke damage can be achieved safely. It can also be used more aggressively when a structure is "fully involved" and the smoke is obstructing the nozzlemans view of the hotspots.
High-rise buildings sometimes also incorporate fans to produce a positive pressure in stairwells and elevator shafts to reduce smoke infiltration into those spaces.
When glass windows in a burning structure burst from internal pressure and heat, or the fire burns through the roof, it may be said to have "auto-ventilated" or "self-ventilated."
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5. Reasons for Ventilation
To remove or control:
Hazardous/obnoxious odors
Smoke and smoke odor
Odors
Asbestos
Chemicals
Gases
Fumes
Particulates
Smoke & Smoke odor=two different items here, what is burning? Is it controlled? You never want to put ventilation in place if you are not sure the fire is extinguished, doing so could cause a flair up of fire. Numerous chemicals are also in smoke-watch exposure.
Odors:
Most common is the removal of unwanted odors, like the burnt popcorn.
Also, chemistry or science buildings, gyms, locker rooms and dorms are other examples.
Asbestos SPECIAL TRAINING REQUIRED
Chemicals Knowledge of chemicals in the area is important, there may be special requirements or PPE required, seek advise on this topic
Gases IS IT FLAMMABLE? IS YOUR FAN SAFE? Where are you venting to?
Fumes in tanks and confined spaces require additional testing and monitoring
Flammable gases can ignite if not managed properly
Are the gases heavier or lighter than air?
Toxic fumes To control exposure levels
Fumes Vehicle exhaust, controlling CO build up
Particulates Control microorganisms, dusts, etc.
Burned Popcorn-Ugh!
Note: There are specific requirements for certain contaminants that require specialized training and equipment
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6. Types of Ventilation Vertical Moving air up and out
Horizontal (lateral)
Moving air out through windows and doors
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7. Methods of Ventilation
Mechanical/Forced
Fans
Cooling
Dilution
Exhaust
Circulation
Filtration
Scrubbers
Exhaust Systems
Chemical
Mechanical ventilation is utilized when natural ventilation or a quicker process is needed.
In a hazardous atmosphere it may reduce concentration levels of chemicals, flammable vapors, toxic vapors, below dangerous levels to safe or normal levels.
If contaminant is generated at high rate, large amount of ventilation air is required. There maybe situations where you are unable to lower a concentration. For example, if you’re trying to ventilate a gas leak and cannot maintain the flow, emergency services should be contacted.
Can be expensive to move large quantities of air. With cost of electric, fuel or renting additional equipment along with the money to pay personnel.
Does not always reach local sites where chemical concentrations may exceed permissible levels (PEL). If the area is too large or remote from the intake it could be hard to keep maintain the flow.
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8. How Air Moves Natural + No cost Difficulty controlling
Increased time to utilize
Mechanical/Forced
+ Easy to control direction
Need power source
Fumes
Cost
Wind
Drafts
Pressure
Negative
positive
Vacuum
Temperature
Mechanical
Forced
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9. Ventilation Safety
Never use gasoline powered fans inside a building, structure or confined space
Make sure fans are grounded
If a flammable atmosphere exists make sure fans are intrinsically safe (i.e. explosion proof)
Ensure area safe to set up equipment
Trip hazards – block off area, wires, fans
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10. Ventilation Steps Determine: What the problem is Where it is located
Smoke, odor, chemical, etc.
Where it is located
What type of structure, building layout, occupancy
What is the cause or source
Origin of problem that needs ventilated
Is it safe for me
Main concern: can you do it safely without endangering yourself or others?
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11. Ventilation Steps If unknown or dangerous:
Seek further assistance from Environmental Health & Safety (EHS)
Emergency services (either public or private contractors may be considered an option)
911
• If material can be identified and handled in a safe manner proceed to the next step
• Follow company policy
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12. Ventilation Steps If you can start ventilation:
Determine where you are going to direct the flow of air
Avoid contaminating clean areas
Avoid directing into high occupancy area
Will it be a nuisance or hazard to anyone down wind?
If odors or other conditions are too strong, contact EHS for further evaluation
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13. Vapors
Check the corresponding Safety Data Sheet (SDS) for the product being ventilated
Review “Vapor Density” listed on SDS
Vapor Density = measure of a vapor’s weight when compared to air (air assigned value of 1)
Denser vapors tend to sink to floor level, less dense vapors tend to rise to ceiling level
Vapor Density:
Air=1.0
Vapors or gases with number higher than 1.0, i.e. 2.0, 2.5, 3.0, are that many times heavier than air will “sink” in atmosphere.
Vapors or gases with number less than 1.0, i.e. 0.9, 0.8, 0.7 are lighter than air and will rise in atmosphere.
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14. Opening & closing doors
Directing Air Flow
Opening & closing doors
Opening & closing windows
Hanging plastic tarps in uncontaminated areas
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15. Directing Flow
A draft is better created with the flow coming in one direction and funneling out the opposite end
Closing additional doors or windows will increase the flow of air out of room/area
Additionally, remove any screens or curtains that may be in the way
Make sure the wind is not naturally coming in the way you intend to exhaust the odor
Ventilation can be positive or negative. Examples:
You can positively pressurize a location by blowing air into it toward an evacuation opening such as window or door.
You can use negative pressurization by drawing air from a location.
You can also use negative and positive together; blowing into a room and withdrawing from a remote location.
Some companies like those cleaning out gasoline or oil storage tanks (scraping scale from the inside walls) will only use negative ventilation. To positively pressurize creates a “hurricane” of scale inside the tank and can injury personnel and/or reduce visibility by putting materials into suspension.
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16. Close off open hallways or unaffected areas
Directing Flow
Close off open hallways or unaffected areas
Utilize plastic tarps or plastic sheets
Shower curtains with open hooks also work
Tension rods
Duct tape
To meet standards, some items will require top to be more sealed up to prevent additional contamination
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17. Let’s Ventilate How could you ventilate this area? Windows
Stairs
Use Natural, Mechanical, Combination of both
Doors
Stairs
Stairs
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18. Example of Stricter Requirements
Asbestos
Asbestos training required
Do not disturb or enter
Required items:
Signage
Negative air machines
Air lock
Restricted entry
PPE (respiratory)
Flooring (9x9 tiles)
Insulation, tiles, ceiling, fire proofing, hot plates, boilers
Asbestos Containing Materials (ACM) Demolition. This program covers these requirements for managing and monitoring the demolition of asbestos-containing materials: Applicability - These regulations define the material type, size and type of demolition project that qualify as ACM.
Notification Requirements - Written for facilities where ACM demolition or removal is occurring, these regulations outline when owners/operators must provide written notification to the Administrator of the EPA (generally, 10 days in advance and also when schedule changes occur). Notification documents required of removal contractors also generally contain description of the work practices and procedures, and certification of removal.
Procedures for Asbestos Emission Control - These regulations define the emission control procedures required during the actual removal or demolition. These practices include, but are not limited to: --Wetting the material to limit fugitive dust and sealing the ACM with leak-tight wrapping prior to dismantlement. --Avoiding the damaging or breakup of the removed material. --Providing glove-bag system and ventilation to contain all emissions.
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19. Evaluate the Area
Evaluate before allowing occupants (e.g. students, staff, etc.) to return
Senses may not be the best testing factor; may
depend upon what is being ventilated
▪ Use meters if necessary
▪ Utilize someone not on site previously (some items may desensitize your ability to smell them)
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20. Summary
Ventilation is not difficult, but does take some thinking as to where to move contaminated air
Never move contaminated air into non- contaminated areas
If necessary, move occupants out of an area before ventilating
Determine the best method for effective ventilation
If material involved is hazardous, or you are not sure: stop and consult EHS for instructions
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21. Questions
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