Smokeeters - Tobacco Smoke Removal Systems

 

How a Smokeeter Removes Tobacco Smoke:

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 Sizing & Placement:
5.1 Area Cleaning Method:
-Efficiency
-Air Changes
-Capacity
-Air Pattern
-Room Sizing
5.1.2 Periphheral Air Circulation Pattern:

 

Section 5 Sizing and Placement


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.
5.1 Area Cleaning Method
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
Efficiency
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.

Air Changes
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
Capacity    
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

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Air Pattern
 
Air cleaners must be sized and strategically placed to create air patterns that will maximize their perform­ance. Unless this is accomplished, the air cleaner, no matter how efficient, will operate at reduced levels of effectiveness in cleaning room air.
Two primary air patterns are used by SMOKEETER/
CRYSTAL-AIRE:
1.       Peripheral Air Pattern — Units are mounted on the ceiling or high on the wall to establish a flow of air around the room that is above the objects and people in the room. This pattern works on the prin­ciple that smoke rises, becomes trapped in the air pattern, and is collected by the air cleaner. See Figure 5-1A.
 
2.       Ceiling Sweep Air Pattern — Units are mounted in the ceiling with the intake and supply grilles flush with the surface. The curved supply grilles keep the air movement at ceiling level. A self-contained SE 22/SE 24 unit is shown in Figure 5-1 B while a Model FS/LS system is shown in Figure 5-1C.
 

 General Considerations

Before getting into the design formulae, some general observations must be addressed.  SMOKEETER/CRYSTAL-AIRE, or any other air cleaner, is not a total air processing system.  It does not remove carbon dioxide.  It does not replenish oxygen.  For these reasons, some fresh air must be supplied to the room.  The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) recommends 40 to 60 CFM of fresh make-up air per person in gathering areas.  Using SMOKEETER/CRYSTAL-AIRE, this requirement can be reduced to only 15 CFM per person.  This minimum requirement for fresh make-up air should never be omitted.

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Room Size

The first two factors are covered in the basic "sizing formula" which yields the total CFM requirements. 

LxWx H x Air changes per hour* = Total CFM required. 60 minutes.

Where: L = Length of room

W = Width of room

H = Height of room *See Table 5-1.       CFM Calculator

Height used is normally 10 feet because this is the optimum height for most installations regardless of actual ceiling height. Where ceilings are higher, the units should still be hung at the 10 foot level, creating an artificial ceiling with the pattern. If the ceiling height is lower than 10 feet, actual ceiling height may be used for calculating capacity requirements.

EXAMPLE:

An office is 30 feet wide, 40 feet long and has a 9 foot ceiling. From Table 5-1, the air changes recom­mended for an office area is 4. Using the formula, the total CFM is determined:

LxWx H x Air changes per hour* = Total CFM required 60 minutes.

40 x 30 x 10 x 4 = 720 CFM 60

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Summary Sizing
(1)   Calculate room size in cubic feet.
(2)   Determine number of air changes per hour for application (Table 5-1).
(3)   Determine CFM requirements:
L x W x H x Air changes per hour* = Total CFM 60 minutes.       Required
(4)   Determine equipment recommendation: Total CFM    = Number of
CFM Rating of Model                    Units Needed
(5)   Verify recommendation against load factor. If load factor is higher, increase equipment recom­mendation accordingly. (Table 5-3).
(5A) If CRYSTAL-AIRE Media application, in­crease equipment recommendation based on Table 5-4.
5.1.2 Peripheral Air Circulation Pattern
Once the equipment requirements have been deter­mined, the next task is to strategically place the equip­ment to develop an air pattern around the perimeter of the room. Unless this is accomplished, the air will not be properly cleaned. Many applications are simple — the room is a basic square or rectangle and there are few, if any, obstacles to impede the air pattern. How­ever, there are rooms with odd shapes, ones that have alcoves, and ones that are decorated with items that impede airflow — canopies hanging from the ceiling, large ceiling beams and others. All of these things must be considered when choosing the best location to place the equipment.