The author is into design of dust collection system for woodworking shops.

1. PRESENTATION ON
DUST COLLECTION
SYSTEM DESIGN
FOR
SMALL WOOD -
WORKING SHOPS

2. 1. Most of the wood working shops in Surrey have
installed portable Dust Collectors which is a Fire
hazard because of:
• Long flexible plastic pipes.
• Insufficient dust removal from the machines.
• No interlocking between Dust Collectors M/C.
• No grinding & bounding.
2. Few shops have installed Enclosurless Dust Collectors
with a capacity of anywhere from 2000 ~ 4000 CFM.

3. 1. Dust Collector is installed near the Exit Door/ Way Door and area
routinely occupied by personnel is within 20’ which is contrary to
NFPA 664-8.2.2.5.1.4(F).
2. Machines/ Equipment is installed within 20’ of Dust Collector.
3. Poor ducting layout design.
4. No Interlocking of Dust Collectors with Machines/ Equipment.
5. No Grounding/ Bounding of ducting, machine and dust collector.
6. No Back blast damper to prevent flow counter to normal flow in
the Ducting.

4. We have conducted a detailed study on Dust Collection System in use at a
Kitchen cabinet manufacturing shop located in Surrey for the purpose of our
presentation to:
1. Understand the current Dust Collection System and its non compliance to
NFPA 664 and BCFC.
2. Prepare a problem countermeasure sheet.
3. Calculate air flow required for the shop and compare with the existing Dust
Collector Capacity.
4. Study the existing ducting layout and modify it with reference to calculated
air flow.
5. Suggest additional safety features to comply with our requirement of NFPA
664 and BCFC and Work Safe BC.

5. Existing Dust Collector: An enclosureless dust
collector – DOC16E of spec Air with the following
features is illustrated:
• 20 HP blowers @ 5000 CFM.
• Static Pressure is 14”WG.
• Inlet Diameter is 16”.
• 36 Bag type filters arranged in a pattern of 6x6
in a dust collector housing of 60”x 60”
• Each filter is 8” in diameter and 5’ in height.
• Filtration Area is 638 Sq. feet.
• Air to cloth ratio @ 5000 CFM is 7.8:1

6. AIR FLOW (CFM) CALCULATION
ITEM
SLIDING
TABLE SAW
EDGE
BANDER BORING TABLE SAW CNC
HOOD DIA (INC) 6.00 6.00 6.00 6.00 5.00
HOOD DIA (FEET) 0.50 0.50 0.50 0.50 0.42
DESIGN VELOCITY (F/M) 4000.00 4000.00 4000.00 4000.00 4000.00
AREA = n*D2/4 0.20 0.20 0.20 0.20 0.14
NUMBER OF HOOD 1.00 1.00 1.00 1.00 2.00
CFM = V*A 785.00 785.00 785.00 785.00 545.14
TOTAL CFM 785.00 785.00 785.00 785.00 1090.28
DESIGN AIR FLOW 4200.00
At the time of this study, the following equipment was being used. The air flow requirement
of each machine is based upon an in-duct target velocity of 4000fprn (20m/s):

8. SL. NO. PROBLEMS CODE COUNTERMEASURE
1 Dust collector is within 20 feet of
Egress door and area routinely in use
by operator.
NFPA 8.2.2.5.1.4(7)(F) Relocate the DC to another place so
that it is isolated from the operator
by 20 feet.
ŸŸŸŸBuild a room 2 hours fire rated
drywall with steel door openable and
open from the top. Detailed space
given in our drawings.
2 Dust collector is not interlocked with
dust producing equipment.
BCFC 2012; 5.3.1.8
NFPA 664: 8.2.2.1.4
All machines are to be interlocked
with DC so that no M/C can be
energized. Unless the dust collector
is energized, this will prevent M/C
from being turned on.
3 No back blast damper is installed in
the ducting system.
NFPA 664: 8.2.4.2 Install a blow back damper as shown
in the design drawings.
4 Ducting is not Grounded/Bounded. BCFC 2012:5.3.1.5;
NFPA 664:8.2.2.2.1.8
Electric grounding/bounding of the
ducting system is required to reduce
the risk of spark generation within
the ducting system.
5 No maintenance plan for dust
collection system.
Prepare annual maintenance plan.
6 Ducting layout is not as per design. NFPA 8.2.2.2.1.5(A)
NFPA 8.2.2.2.1.5(B)
Redesign ducting layout as per the air
flow requirement.

10. Additional recommendation to meet NFPA664 &
BCFC:
1. Dust collector to have a heat detector interlocked to
main electrical panel so that in event of heat build-up
the dust collector should shut down.
2. A buzzer is also required so that it give signal to all
workers during any emergency occur.
3. Install limit switch on the door interlocked with main
panel so that whenever someone try to open the door
without shutting the dust collector, the system shuts off.
4. Sprinkler system to be extended to the Room of dust
collector as the building is already sprinklered and install
ESFR sprinkler head just above the filter bags.
Reference Code: NFPA 664-A.8.2.2.5.1.4(7).