2 - Unit review exercises Flashcards
1
Q
- (816) The pressure of moving air is always measured in the direction of airflow. What kind of
pressure is this?
a. Always positive.
b. Always negative.
c. Negative on the blowing side.
d. Negative on the exhausting side.
A
Always positive.
1
Q
- (817) Less resistance and better contaminant capture in a ventilation system happens by using
a. an air cleaner.
b. higher velocities.
c. elbows in the ducting.
d. a flange or tapered hood.
A
a flange or tapered hood.
2
Q
- (817) Where should you expect the static pressure (SP) to become more negative in a ventilation
system?
a. Within the hood.
b. At the hood throat.
c. At the inlet to the fan.
d. At the outlet to the fan.
A
At the inlet to the fan.
3
Q
- (818) Which type of velocity refers to the speed of air at a point in front of a hood that is needed
to pull contaminants into the hood?
a. Face.
b. Duct.
c. Capture.
d. Transport.
A
Capture.
4
Q
- (819) What are two parameters at a given point in ventilation systems that are needed to calculate
the airflow volume (Q)?
a. Area and pressure.
b. Area and velocity.
c. Velocity and pressure.
d. Diameter and velocity.
A
Area and velocity.
5
Q
- (819) The cubic feet per minute (cfm) through a cross-sectional area of a ventilation booth is the
same as
a. area.
b. density.
c. velocity.
d. static pressure (SP).
A
velocity.
6
Q
- (820) In dilution ventilation, a slight negative pressure is desirable when
a. an adjoining room is normally occupied.
b. the contaminant is fairly high in toxicity.
c. an adjoining room is normally not occupied.
d. the contaminant is fairly low in toxicity.
A
an adjoining room is normally occupied.
7
Q
- (820) What circumstance would result in a high K factor?
a. Adequate mixing of air.
b. Higher contaminant toxicities.
c. An even evolution of contaminant.
d. A high occupational exposure limit.
A
Higher contaminant toxicities.
8
Q
- (821) Other than good contaminant control, what is the biggest advantage of local exhaust over
dilution ventilation?
a. Less noise.
b. Lower operating costs.
c. Better protection for equipment.
d. Easier worker access to the process.
A
Lower operating costs.
9
Q
- (821) The purpose of using splitter vanes, multiple takeoffs, or baffles inside of a local exhaust
hood is to provide
a. a reduction in system resistance.
b. an increase in hood static pressure (SPh).
c. proper discharge of air away from inlets.
d. uniform air distribution across the hood face.
A
uniform air distribution across the hood face.
10
Q
- (822) What determines the capture velocity that must be used for a properly designed canopy
hood?
a. Number of open sides.
b. Height of the canopy hood.
c. Location of the side curtains.
d. Contaminant containing tank size.
A
Number of open sides.
11
Q
- (823) In a routine survey, ventilation system data collected during the routine assessment should
be compared to
a. key parameters.
b. factory findings.
c. previous routine survey data.
d. data collected during the baseline survey.
A
data collected during the baseline survey.
12
Q
- (824) What instrument is used to take face velocity measurements and actually converts velocity
pressure (VP) to velocity readings?
a. U-tube monometer.
b. Inclined manometer.
c. Thermal anemometer.
d. Swinging vane anemometer.
A
Swinging vane anemometer.
13
Q
- (824) What important procedure must you follow to obtain accurate readings with a velometer?
a. Hold the probe parallel to the airflow.
b. Always, make two traverses at right angles to one another.
c. Choose a section of the duct with smooth flow for measurement.
d. Hold tube so that the mark aligns with the side of the duct and point tube directly into the air stream.
A
Hold the probe parallel to the airflow.
14
Q
- (824) What may be indicated by a very strong flow coming in an open door of a room containing
a local exhaust system?
a. Adequate makeup air.
b. Excessive cross drafts.
c. Inadequate makeup air.
d. Proper discharge of air away from inlets.
A
Inadequate makeup air.
