SMOKEETER captures tobacco smoke, dust and pollen particles much like a magnet. As contaminated air is drawin through the unit, the particles are given a positive charge by the ionizer. These charged particles are then deposited on negatively charged collecting plates as air flows through the unit to be recirculated as clean air.
5.0 SMOKEETER/CRYSTAL-AIRS Sizing and Placement
To engineer an air cleaning system, equipment capacity and air circulation must be addressed in the same way in which an HVAC system is designed. The primary difference is that the air is being cleaned, not tempered. Just as it is with HVAC systems, undersizing and/or poor air circulation will result in poor air quality.
SMOKEETER/CRYSTAL-Al RE units can be engineered to solve poor air quality problems using two different methods. One is area cleaning. The other is ducted or source capture. Both equipment capacity and air circulation are different for the two methods and are treated separately.
The area cleaning method applies to applications where smoke or other contaminants are generated in locations too numerous or too large making source capture impractical. The SMOKEETERS/CRYSTAL‑
AIRES are used to clean ambient air. Restaurants, lounges and offices are examples of area cleaning applications to remove tobacco smoke, bacteria, viruses, dust and other airborne particles. Autobody repair shops and woodworking shops are examples of area cleaning applications to remove airborne particles generated by painting, sanding and grinding work processes.
There are four factors that influence overall effectiveness in an area cleaning application:
1) Efficiency
2) Air changes
3) Capacity
4) Air pattern
The three most commonly used methods of testing an air cleaner's efficiency are the weight method, atmospheric dust-spot method and the cold DOP test_ The SMOKEETER/CRYSTAL-AIRE Air Cleaner is efficient by any standard. See Section 3.3 for additional information.
An air cleaner is required to filter the air in a given space a prescribed number of times each hour to maintain a satisfactory level of cleanliness.
The number of air changes required to attain a level of cleanliness has a limit. Particles cannot be removed from the air in a room any faster than they mix with the air and be collected at the air cleaner. To go beyond 10 air changes may not increase the effectiveness of the air cleaning system (refer to Figure 3-12). In addition, a higher number of air changes creates drafts, causing discomfort to the occupants of the room.
The number of air changes needed depends on the generation of contaminants in an application. Recommended air changes per hour for various applications are given below.
LOAD
|
APPLICATION
|
AIR CHANGES
PER HOUR
|
Light
|
Offices
Restaurants
|
4 to 6
|
Average
|
Bingo halls
Lounges
|
6 to 8
|
Heavy
|
Autobody
Welding
|
8 to 10
|
TABLE 5-1
Air Changes per Hour
SMOKEETER/CRYSTAL-AIRE Air Cleaners have a capacity rating based on the amount of air the blower can deliver inside the cabinet. This volume of air through the air cleaner is expressed as CFM, or cubic feet (of air) per minute. SMOKEETERS/CRYSTALAIRES have been tested in an AMCA chamber at UAS to insure that the air volume is correct. The CFM delivery rate can vary on all SMOKEETERS/CRYSTALAIRES by either a selection switch to change the motor speed or a vari-pitch pulley on belt driven models.
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For sizing purposes, the following chart shows the nominal CFM ratings for SMOKEETER/CRYSTALAIRE models.
MODEL
|
CFM
RATING
|
TYPE OF
AIR PATTERN
|
SE 10
|
250
|
peripheral
|
GC
|
340
|
peripheral
|
SE 30
|
420
|
peripheral
|
SE 40
|
950
|
peripheral
|
SE 50
|
1500
|
peripheral
|
SE 22
|
300
|
ceiling sweep
|
SE 24
|
1000
|
ceiling sweep
|
FS
|
885*
|
ceiling sweep
|
LS
|
1600*
|
ceiling sweep
|
CC
|
1150
|
peripheral
|
DC
|
2200
|
peripheral
|
QC
|
4400
|
peripheral
|
DK
|
3000
|
peripheral
|
QK
|
6000
|
peripheral
|
MA
|
2300
|
peripheral
|
MB
|
3000
|
peripheral
|
C/A MOD. SYS.
|
1500**
|
ceiling sweep
|
*Airflow rating of unit without ductwork. **Airflow rating at .5 in. ESP
TABLE 5-2
CFM Rating / Type of Air Pattern
CRYSTAL-AIRE Media Air Cleaners should be sized based on average particle size and CFM rating. See Table 5-4 for sizing.
SMOKEETER/CRYSTAL-AIRE electrostatic Air Cleaners also have a capacity rating based on smoker count or load factor.
This factor is used in applications where an unusually large number of people gather or where the contaminants generated by the work process are unusually heavy.
In tobacco smoke applications, the load factor is based on the number of smokers who occupy the area's rated capacity. Each SMOKEETER/CRYSTAL-AIRE electrostatic air cleaner has been rated for a number of people/smokers.
MODEL
|
*NUMBER OF
PEOPLE
|
NUMBER OF
SMOKERS
|
SE 10
|
10
|
3
|
GC
|
20
|
6
|
SE 30
|
22
|
7
|
SE 40
|
60
|
18
|
SE 50
|
90
|
27
|
SE 22
|
20
|
3
|
SE 24
|
50
|
15
|
FS
|
50
|
15
|
LS
|
80
|
24
|
*Based on "average" population of 30% smokers.
TABLE 5-3
Smoker Count
Each tobacco smoke application should be verified against these maximum figures before a final recommendation is made. It is possible that an equipment recommendation based on room size alone could result in an inadequate installation due to an abnormally large concentration of smokers. When comparing equipment recommendations based on room size and equipment recommendations based on the concentration of smokers in the room, select the larger of the two recommendations.
Applications for smoke and dust created by a work process can also be subject to an abnormally high airborne particle load factor. Determination of the load factor is a much more subjective decision in this case than in the tobacco smoke applications. (Some criteria that may be used in determining workplace load factor are visual observation, density of work stations, anticipated workload, and pace productivity.
TABLE 5-4
Filter Efficiency |
Number of Air Changes |
|
Dust Spot 52-76 ASHRAE |
Medium Particles
(1-10 microns) |
Small Particles
(sub-micron)
|
90-95% Filter |
Same number of air changes as electrostatic air cleaner. |
1.5 times the number of air changes as the electrostatic air cleaner. |
60-65% Filter |
1.5 times the number of air changes as electrostatic air cleaner. |
NA |