BEO1060829 Ventilation and RP Flashcards
The laws of _____ of _____ and _____ are applied to ventilation systems: mass flow is the same throughout the system and what goes in (supply) must come out (exhaust).
Conservation of Mass and Energy
____ Energy is energy of work.
Kinetic
____ Energy is capable of doing work.
Potential
_____ of _____ states that the total amount of energy in an isolated system remains constant, although it may change form.
Consevation of Energy
_____ (Q) is the quantity of air that passes through a given location per unit of time.
Airflow Volume Q = V * A
The airflow entering the hood of a vent system must _____ the airflow volume leaving the vent system.
equal
What are the two types of airflow?
- Natural
- Mechanical
_____ ventilation circulates air without assisst of a mechanical device.
Natural
_____ ventilation circulates air using a fan or blower.
Mechanical
What are the two types of mechanical ventilation?
- Dilution
- Local Exhaust
_____ ventilation, a form of mechanical dilution, increases the proportion of airborne contaminant. An example is A/C
Dilution
_____ _____ ventilation, a form of mechnical dilution, removes contaminants from work areas at the source of contaminant generation.
Local Exhaust
Inadequate _____ air creates pressure differentials on doors, exits, and windows, and high velocity drafts.
make up
Exhaust vent systems require _____ of exhausted air.
Replacement
_____ pressure systems “suck” air in.
Negative
_____ pressure sytems push air out.
Positive
_____ are used to create the pressure necessary to begin and maintain the airflow by creating pressure differences inside vent ducts.
Fans
Air always moves from _____ pressure to ____ pressure.
Greater to lesser
What are the three types of pressures?
- Static
- Velocity
- Total
_____ pressure is the potental energy of a system and is created by the fan when it sucks air from one side of the system, then delivers it to the other.
Static
Static Pressure upstream of the fan is _____.
Negative
Static Pressure downstream of the fan is _____.
Positive
_____ pressure is the kinetic energy of the system and is the pressure exerted by air in motion.
Velocity
Velocity pressure is always _____.
Positive
Total pressure will be _____ to static pressure.
equal
Air losses due to turbulence are called _____ losses.
Turbulence
_____ _____ is dynamic loss and occurs at the point at which air entering a duct is squeezed just inside the duct.
Vena Contracta
Hoods that are tapered from their openings back to the duct can _____ ____ from the vena contracta.
reduce losses
_____ losses come from the rubbing of air molecules along the sides of the duct.
Friction
There is _____ velocity pressure in the center of the duct than closer to the sides.
stronger
What are 4 major contributors to friction losses in a vent system?
- Rough duct material
- High air velocity
- Small duct diameter
- Long duct length
Friction losses _____ as air velocity _____. (more friction and turbulence)
increase; increase
A small duct with high velocity will experience ____ friction losses that a large duct wth the same velocity.
more
All losses in the system, both upstream and downstream from the fan, add up to the _____ _____ _____ in the form of static pressure at the fan.
total system resistance
The fan must develop enough _____ _____ to overcome the system resistance and also enough _____ _____ to provide the needed air flow (velocity pressure).
static pressure; static pressure
The _____ _____ of the system is what the fan must work against to provide the flow.
total resistance
_____ is a major cause of system resistance and is _____ proportional to static pressure. It is _____ proportional to velocity pressure.
indirectly ; directly
_____ _____ is the velocity of air across the plane of an inlet or outlet of the system.
Face velocity
_____ _____ is the speed of the air in the duct and the transport or conveying velocity.
Duct Velocity
_____ _____ is the speed of air at the point in front of the hood that is required to overcome opposing air currents to capture and remove contaminants from the work area.
Capture Velocity
_____ _____ is the key parameter of the ability of a vent system to control contaminants and is a measure of the quantity of air flowing through the system and is a measure of a fans capacity.
Airflow Volume (Q)
The _____ of an air stream is a one dimensional value.
velocity
The _____ is a two dimensional.
area
Air density varies with _____ and _____, so you must correct readings to standard temp and pressure.
temperature and pressure
Mass flow is the _____ throughout the system.
same
The purpose of _____ ventilation is to control airborne contaminants that may pose a threat to health.
dilution
Dilution ventilation is not to be used for substances with OEEL less than _____ ppm.
100 ppm
Air flow volume is calculated as an _____.
Average
A combination of _____ and _____ is preferred for proper air distribution and dilution.
supply and exhaust
If you are only able to implement one control, supply or exhaust, you should choose _____.
supply
_____ provides a far more directional airflow for better mixing with the contaminant.
Supply
The airflow should flow _____ the worker and _____ the source of contaminant generation.
past; through
_____ pressure keeps contaminants _____ the room.
Negatve ; inside
The _____ _____ _____ is the lowest concentration in percent at which a substance presents an explosion hazard.
Lower Explosive Limit (LEL)
Where does the explosion danger lie?
Between LEL and UEL concentrations
Above the UEL, the concentration becomes _____ _____ to explode.
Too rich
It is standard practice to keep explosive contentration limits at or below _____.
25% of their LELs
_____ is the max amount of a certain chemical vapor that air can hold at a given temp.
Saturation
The TLV of slightly tox materials is _____.
>500 ppm
The TLV of moderately toxic material is _____.
< or = 100 - 500 ppm
The TLV of highly toxic material is _____.
< 100ppm
When two or more hazardous substances are present, their _____ should be given consideration.
combined
If effects of contaminants are _____, the air quality requred to dilute each component of the mixture to the required safe concentration is calculated and the sum of the air quantities is used as the required dilution ventilation.
additive
If the effects are _____, the required dilution ventilation for each component of the mixture should be calculated and the HIGHEST cfm should be used as the dilution ventilation rate.
Independent
What are some advantages to dilution ventilation?
* Less expensive * Less maintenance * Effectively controls small amounts * Good for small, dispersed, or mobile sources
What are some disadvantages?
* Does not completely remove contaminant * Can not handle heavy particles * Requires high volume of make up air * Ineffective for spikes
_____ exhaustion is the most efficient and economical type of industrial ventilation.
Local
_____ relies on mixing contaminants, where as _____ is designed to control a substance at its source so that it never reaches a breathing zone.
Dilution; Exhaust
Inadequate make up air creates _____ pressure in the room that can limit the amount of air exhausted.
negative
When there is an operation that needs local exhaust, always consider an _____ first.
Enclosure
_____ greatly reduce interference from cross drafts so that less air volume is required.
Baffles
What is the first step in determining the correct air volume required?
Identify capture or in-draft velocity requirements.
The capture velocity pertains to hoods that DO / DO NOT enclose a process?
DO NOT
_____ velocity, called the minimum design duct velocity, or simply duct velocity.
Transport Velocity
The velocity required depends on the _____ of the contaminant.
density
More velocity increases the system resistance which increases _____ and _____ on the system.
wear and tear
What are 4 general hood classes?
- Open
- Slot
- Canopy
- Enclosing
_____ hoods do not need capture velocities and therefore require less air flow volumes.
Receiving
Slotted hoods should have an aspect ratio of _____?
0.2 or less
The distance from the hood to contaminant can not be more than ……
the diameter of a circle hood or diaganol of a rectangle hood.
_____ ventilation have generally lower air volumes and the ability to control high toxicity airborne chemicals.
Exhaust
What is the first step in designing an exhaust system?
Identification of estimated flow rates using industrial vent handbook.
What considerations must be made when determining the feasibility of an exhaust system?
* Evaluate process to determine hazards
* Determine if employees will be exposed to hazards
* Determine if exhaust vent is preferred method of hazard control
Where do you install the fan in an exhaust system?
Clean side of the the filter / collection device.
What are the three types of ventilation surveys?
- Initial
- Baseline
- Routine
An _____ test is used to evaluate the new/modified systems performance as compared to the key parameters or contract specs.This test occurs BEFORE the system is put into service.
initial
When performing an initial acceptance test, what type of evalution is performed?
Pitot testing
The _____ survey is performed after the system has been put into service.
baseline
What is the purpose of a baseline survey of ventilation systems?
* ensure system is capable of controlling a hazard below OEEL
* establish baseline parameters for future routine performance tests
The effectiveness of a vent system is confirmed through _____ ____.
air sampling
_____ surveys are performed at a determined frequency to ensure the system CONTINUES to operate properly.
Routine Survey
What type of test is used in a routine survey?
Static Pressure Test
The results of a static pressure test must be within _____ of the baseline value.
10%
For a Pitot Traverse measurement, the points must be at least _____ duct diameters downstream and _____ diameters upstream of any disturbance.
7.5; 2.0
The results of a pitot traverse measurement must be within ____ of one another. If not, must use a third point.
10%
The ultimate test of a vent system’s effectiveness is _____ _____.
Air Sampling
Is it possible for a vent system to exhaust air at a volume less than design parameter, yet still control the contaminant of concern?
YES
What is the most common cause of deficient vent systems?
Inadequate fresh air supply to system
_____ is caused by industrial emissions, auto exhaust, bioaerosols, etc…
Infiltration
The most important factor to any IAQ survey are _____ and _____.
Education and Communication
What are the ideal IAQ ranges?
CO2 = 1000ppm
Relatve Humidity = 40 - 60%
Temp = 68 to 76F
What is the most common reason for unacceptable IAQ?
Insuffient Fresh Air
Where can you find the questionnaire/eval, mandatory questions, for a medical eval of RP?
29 CFR 1910.134
Who determines the workers ability to use a respirator based on med evaluations?
PLHCP
What do BE look for when performing a RP evaluation?
* Maintenance and storage practices
* Work practices
The _____ _____ must develop a written RP plan based on BE evaluation and recommendations and have it approved by BE _____.
workplace supervisor annually
What are the three types of particulate filters?
- N - not resistant to oil
- R - resistant to oil
- P - resistant to oil / oil proof
Sedimentation Capture filters rely on gravity and are capable of filtering particles at _____.
> 3 micrometers
Diffusion Capture filters are capable of filtering particles of _______.
<0.1 micrometers
_____ cartridges are capable of filtering acid and organic vapors, are yellow, and use adsorption or chemisorption.
Chemical
When is SCBA used?
IDLH
O2 deficient atmosphere
_____-_____ air is important to a system because it is capable of eliminating pressure differentials.
Make - Up Air
Where mold is a an IAQ concern, what is the most common symptom?
Allergic Reactions
When dealing with HVAC systems, what are the two most common sources of airflow and/or circulation issues?
“stale air” caused by occupent tampering and/or an unbalanced system
Who is the primary developer of the cartridge change out schedules?
BE
What are the limitations of particulate filters?
- Breathing Rate
- Temp
- Humidity
- Contaminant concentration
- Removal capacity of purifying element
What are the types and colors of chemical cartridges?
- Black = Organic Vapors
- White = Acid Gases
- Green = Ammonia Gas
- Yellow = Acid and Organic Vapors
_____ removes organic vapors by adherence to the surface of activated carbon and will be released if heated.
Adsorpton
_____ impregnated activated carbon removes specific gas / vapor molecules by the formation of bonds between molecules. Stronger than adsorption and will not release them if heated.
Chemisorption
What are the 4 items that must be inspected on respiration protection devices?
- Check function
- Tightness of connections
- Condition of parts
- Elasticity of straps
When respirator devices are issued to more than one employee, how often should they be cleaned and disinfected?
They should be cleaned and disinfected after every use, prior to use by the next individual.
Grade D breathing are for SCBA must meet the following 5 criteria:
- 19.5 - 23.5% O2
- <5 mg/m3 Condensed Hydrocarbons
- <10 ppm CO
- <1000 ppm CO2
- Lack of Odor
What are 5 criteria for selection of respiratory protection?
- Oxygen content
- Physical properties of contaminant
- Airborne concentrations
- OEELs
- Exposure routes and Physiological effects
When evaluating worker activity to determine respiratory protection, what areas must be considered?
- Length of time exposed to hazard
- Work rate - light, medium, heavy work
- Work movements
The _____ _____ _____ is the level of respiratory protection that a properly functioning respirator or class of respirators is expected to provide to users.
Assigned Protection Factor (APF)
_____ _____ _____ is the maximum atmospheric concentration of a hazardous substance from which an employee can be expected to be protected when wearing a respirator.
Maximum Use Concentration
AF Form _____ is the respirator selection worksheet used to evaluate and determine the proper respirator protection.
AF Form 2773
