PyroGuard®Spark Detection

Distributor’s For: Member of:

MacDonald Steel LimitedEnvironmental Systems Division

Typical Small System Pull ThruDiffuser

Equipment

Floor Sweep

Spark Detection

Fast Acting Diverter

Fan

Material Collect in Barrels

Dust Collector

Silencer

Duct System

Pressure Release Venting

Large System Blow Thru, No Return Air

Safety Access Ladder

Deluge System

Fast Acting Abort Gate

Airlock

Fan

Pressure Release Venting

Spark Detection

Outlet

Inlet

Air Flow Round Unit

Clean Air Outlet

Small Particles in Air Flow

Inlet

Cyclonic Separation

0102030405060708090

100

0.3 -0.4

0.4 -0.5

0.5 -0.7

1.0 -1.5

1.3 -1.6

1.6 -2.2

2.2 -3.0

3.0 -3.8

3.8 -4.6

Efficiency

Beane T-150 Media As the chart shows the efficiency rating for a 4.6 micron is capability is 99.99 %The efficiencies start to increase at the 2.2 to 3.0 micron stage at 78.15%

Filter Media

Typical Collectors

Filter Media “Bags”

Clean Air Outlet

Cleaning Mechanism (Shaker, Reverse Air, Pulse)

Types of Collectors

ØPulse

ØShaker

ØReverse Air

Media Types

ØBag

ØCartridge

Dirty Air Inlet

Pulse CollectorsClean Air Outlet

Inlet

Material Outlet

Cleaning System

Clean Out DoorSupport Structural

Pulse CollectorsPulse Tube

Valve

Manifold Plate

Quick Disconnect

Bag and Cages

Airline Connection

Shaker Unit

Material Collection

Pressure Release Vents

Inlet

Filter Media

Fan

Outlet with Fire Curtain

Shaker Motor

Thermostat

Back Pressure Damper

Shaker Type

Hanger BearingsJ-Hooks

Motor and Gear Box

Pull Thu System Shown

Reverse Air Collectors

Shoe

Outlet

Man Door

Blower Fan

Bags

Pocket

Gear Box

Rotary Airlock

• Airlock with motion Sensor

• 4 Bolt Bearings • Rugged Gearbox• TEFC High

Efficiency Motor• Four Neoprene

Blades in Contact at All Times

Material Inlet

Outlet

Abort Gate

• Actuation time of approximately 400 milliseconds for models CW-6 through CW-41 (approx. 500 ms for CW-45 & larger) with loaded torsion springs and gravity assist.

Back Pressure Dampers

Inlet

Inline Damper

Airflow

Movable Door

Airflow

Outlet With Fire Curtain

Clean Air Flow

Fire Curtain complete with Fusible line

DiffuserAir Inlet

Air Outlet

Explosion Ventilation

• Panels or Doors that release or burst when pressure rises with in a unit.

• Ontario Fire Codes list NFPA 68 1994 edition for explosion venting calculations.

• Canadian Fire Codes list NFPA 68 2002 edition for explosion venting calculations. It also states a minimum of 0.1m2 per cubic meter of volume (5.3.1.4). 35 to 1

• NFPA 68 is now version 2007

Explosion Panels

FikeVMax

MacDonald Steel Burst Panel

Flame/Explosion Suppression

• FIKE makes several products that are designed to suppress explosions and that offer flameless with limited particle emissions.

Bag Filter

Snap Ring & Collar

Cloth – Filter Media Hanging Strap

Typical Filter Media

Cartridge Filter

Ø325 ft2 of media

FARR GoldconeCartridge, media inside filter as well. More Surface contact area

Canadian Fire Code - Dust Producing Processes

• Section 5.3• 5.3.1.2 Dust Removal• 5.3.1.3 – Dust Collection Systems

– Calls up NFPA 664 for wood dusts, possibly should read 654 for dust collection process in general.

Canadian Fire Code cont..

• 5.3.1.4 Dust Collectors• Collectors having capacity greater than 0.5

m3/s (1000 cfm) to be located outside unless vented to the outdoors. Explosion prevention system. Or in a fire rated room when explosion ventilation outside.

Ontario Fire Code – Dust Collection

• 5.10 Combustible Dust Producing Processes

• 5.10.1.53)

a) Returned air should not create a a explosion hazard in the building, (abortgate or diverter)

b) The exhaust fan and ancillary equipment are shut down in the event or fire or explosion in the collector

Ontario Occupational Health and Safety Act

• Requires that a PSR on a dust collector that handles explosive material must be signed by a professional engineer.

• If dust collector does not handle explosive material it may not require a professional engineer to sign the PSR.

NFPA Dust Collection

• Which item will not explode?– Wood dust – non dairy coffee creamer– Aluminum– Salt– Phenolic resin– Paper Dust– Sugar

NFPA 654

• The specified particle size for defining a combustible dust is based upon it particle size and diameter, the value is generally citied as 420 micorns

• This will pass through a US #40 sieve• Salt will pass through the sieve, 75% of

table sugar will pass through the sieve

Common Explosion Factors

• Dust Explosion Hazard not recognized

– WHIMS do not indicate if a dust is explosive or not and what level it becomes explosive.

– WHIMS do not indicate maximum Kst or Pbarfor a material.

Common Explosion Factors

• Engineering Controls not adequate– Improper duct velocities– Lack of spark detection– Lack of Explosion relief panels– Lack of Explosion suppression– Lack of system isolation

Common Explosion Factors

• Dangerous dust accumulations– If good house keeping practices are not followed you

can get a build up of dust through out the plant. The dust could cause an explosion through a static charge when compressed air is used to clean an area.

– If there is a explosion, this can dust dispersed by the shock wave of the explosion in concentration that can allow it to explode. Leading to dangerous secondary explosions.

– When doing house keeping, look up!

Common Explosion Factors

• Poor Dust Collector Design or Poor system Maintenance– In adequate explosion venting– Pressure relief door maintenance program not

followed.– Basic system maintenance not followed.

Bearings not maintained, cleaning system not inspected

– If you have more than 1/8” of wood dust (20 lb/ft3) you have too much dust.

In the USA

• There is currently a national emphasis program to inspect facilities that handle explosive dust due the explosion and fire at Imperial Sugar Company in Georgia. – 13 killed, 32 injured.– SHIB 07-31-2005

Definitions

• Deflagration– Propagation of a combustion at a velocity that is less

than the speed of sound in the unreacted medium. Can be engineered controlled. The flame is consuming the dust.

• Detonation– Propagation of a combustion at a velocity that is

greater or equal to the speed of sound in the unreacted medium. Generally this can not be engineered controlled. Not normal in dust explosions

Defenitions

• Kst– Is the maximum rate of pressure increase normalized

to the volume in which the rate was measures. (speed of the explosion)

• Pmax– Is maximum pressure produced during the explosion.

• These are the two key material variables for determining the number of pressure relief doors

Things to look for

• If the material is explosive the system should have– Spark detect/extinguish in front of the unit and after the fan if its

blow thru– Pressure Relief Panels in the unit or Fire Suppression– Path of the fire ball from the pressure relief panels– Abortgate or fast acting diverting on return side if air is returned

to the building– Temperature sensor in unit– Fire Curtain on Outlet of unit– Back Pressure damper at inlet– Deluge/Sprinkler system in collector– Good House keeping of plant

Maintenance Records– Are the following items been inspected at regular intervals

• If there is a spark detection/extinguish system when was it last inspected/tested?

• Have the pressure relief panel’s been inspect to make sure they can operate properly?

• If there is a deluge system has it been inspected?• Has the cleaning system been inspected to make sure it

operates properly, is all the media in place?• Has the thermostat been checked?• Has the fire curtain been inspected?• Has the backpressure damper been inspected• Has the abortgate/diverter been tested/inspected• Is there settling of material in the ducts (proper duct

velocities)?• If the air is being returned is it free of visible containments?

Questions?

• If you have questions and wish to contact us,

• Jim Goad – 519-620-0400 ext 3283– jgoad@macdonaldsteel.com

• Richard Stevenson– 519-620-0400 ext 3242– rstevenson@macdonaldsteel.com