Safety Aspects of Thermal Fogging Working in confined spaces

(refuse chute) Presented by Heng Yiwei

Governing Council Member Singapore Pest Management Association

Key Factors

• Proper equipment – High Quality

– Maintenance

• Operator professionalism – Well trained in machine functions

– Safety Awareness

– Adherence to Standard Operating Procedures

• Alternative methods – Innovations that enhances safety and

minimise/nullifies the factor of human error

Quality of Equipment

• Quality of Fogger (WHO specifications) – Materials of construction

– Weight

– Pesticide tank and fittings

– Fuel tank capacity

– Air pump

– Discharge System

– Straps and fastenings

– Sprayer performance (CO and NOx lower than mist blowers suitable for indoor)

• Understanding of equipment (What quality means?)

Quality (WHO specifications)

AF35

Performance (Heat)

• Distance between point of injection and end of fog tube influences temperature at point of injection – Additional opening for cooling air (high quality units) – Active ingredient only for a few milliseconds in the hot

gas stream – Low temperature at point of injection (high quality

units) – Integrity of Active Ingredient kept, increase efficacy

decrease wastage – Cool fogging temperature (fog BTI – IMR TEST)

Distance between: point of injection / end of resonator Competitor – 210 mm / AF 35 – 30 mm

Performance (Heat)

Performance (Heat)

630 °C

1100 °C AF 35 K 10 SP

30 mm

1000 °C !!!

about 300 °C with ventilation

1100 °C

135 mm

Performance (Heat)

195 mm SF 150

20 mm AF 34

235 mm SS 150

360 mm Sphwk

690 C° SF 150

590 C° AF 34

930 C° SS 150

950 C° Sphwk

180 mm Lgry 1000 C°Lgry

Equipment Maintenance

• Maintenance – Ensure the proper functioning of fogger – No carbon build up – No flame problems

• Ease of maintenance (technician willingness) – Frequency – Procedure

• Water base fogging – No carbon build up – Less maintenance required – Flame problem nullified

Spare Parts and Tools

Tools, funnels, spare gaskets and membrane that

are required for routine use are supplied with a

clear list of spare parts, illustrated and coded.

Operation and Maintenance Manual

The manual in English and German supplied with the test

machine included complete instruction on the use, maintenance

and cleaning of the equipment and gives a list of all parts.

Double open

ended spanner

(14/12mm)

Brush for swirl vane

Line, long

Dossage nozzle 0.8/1.0/1.2

Pipe cleaning tool

Carrying belt

Gasoline funnel

Screw driver

Gaskets Tool bag

Solution funnel

Double open

ended spanner

(8/10mm)

Pipe cleaning tool

1. Clean Resonator with pipe cleaning rod

Removal of Fog Tube

3 Step Maintenance

2. Air in-take valve –clean & replace gaskets

3. Mixing chamber + Swirl vane - decarbonizes

3 Step Maintenance

Operator Professionalism

• Well trained in machine functions – Reading of instruction manual – Training conducted by qualified suppliers – In-house training by qualified professionals – Refresher to be done regularly – Proper Handling

• Safety awareness – Operation of machine – Environment – Acute appreciation of situation – Safety Checklist

• Standard Operation Procedures – Observe SOPs for different situations – Personal standards > in house standards > industry standards

“Solution Socket-AF35-114” – Do not over tighten

and ensure proper installation

“Fog Tube-outer tube-

AF35-108” Do not mishandle

“Resonator-inner tube-AF35-97” –

Properly cool down the

machine after fogging, don’t flush water for fast cool down, this will reduce lifespan of the

Resonator. “Solution Tank-AF35-1” - Made

of stainless steel, durable

material

“Petrol Tank-AF35-10” – place

it at the flat surface and don’t

drag it

“Swirl vane” -Decarbonizes

and clean once a week

“Nozzle-AF35-117” – Do not

over tighten

“Solution Tap-AF35-120” – Turn to

“ventilate position” for clearing of excess

chemicals (few seconds) and turn to “off position” before

stopping the machine

Note : Daily maintenance ( Recommended after usage)

“Air intake valve – AF35-30”

Proper Handling

“Solution Tap , Check for no leakage.

“Solution Socket, Check for leakage,

crack and no obstruction.

“Fog Tube, Check for no carbon build

up , no obstruction

and no dent.

“Resonator tube, Check no carbon

build up and no crack

“Solution Tank-Check for no leakage,no

dented

“Petrol Tank-Check for no leakage, no dented and

petrol tank cap must always be able to tighten

“Swirl Vane and Mixing Chamber,

Check for no petrol leakage and no carbon

build up.

“Nozzle , Size 0.8 or 1.0

Check for leakage , no crack and no

obstruction .

“Solution tank cap, Check for no leakage,

no crack and must always be able tighten.

“Ignition Coil Cable, Check for no

damage

Safety Check List; 1. Fog Tube: Pass / Fail 2. Resonator: Pass / Fail 3. Solution Socket: Pass / Fail 4. Nozzle: Pass / Fail 5. Solution Tank: Pass / Fail 6. Solution Tank Cap: Pass /Fail 7. Petrol Tank and Cap: Pass / Fail 8. Ignition Coil Cable: Pass /Fail 9. Swirl Vane / Mixing Chamber:

Pass /Fail

Safety Checklist

Case study – Fogging in Refuse chute

• Appreciation of factors involved: – Operator safety – Thermal fogger (heat) – Confine space – Secondary gases from refuse (methane)

• Operator Safety – Proper PPE

• Thermal fogger – Equipment of proper quality – Proper maintenance – Adequate amount of petrol and fog solution ( or auto-cutoff

device) – Proper timing of machine (no flame problems) – Backflow into petrol tank causing explosion is not possible

Case study – Fogging in Refuse chute • SOP for fogging in confine spaces

– Ventilation

– Well maintained fogger = no flame problems = no ignition of gases

– Fogging distance

• Importance of Thermal Fogger’s quality – Material of resonator and fog tube

• Heat distribution

• Tests(fine spraying of petrol) done to ensure that ignition is not possible without source of ignition (i.e. spark)

– Oil base fogging in confine space

• Test conducted to determine amount of Ai compromised using various foggers with different points of injection

• Fogging in confine spaces does not result in flame problems

• Water base fogging with carrier and dual purpose fog tube(patented)

– Safe – No flame problems – Less maintenance – Efficacy tested and proven – More than 100m efficacy

• Auto cut-off device(Pneumatic) – No flame overflow – Safety feature should machine stop suddenly – No need to worry if petrol empties

Alternative Methods

• Training is important to ensure proper handling of equipment and proper safety procedures are observed

• To minimize human error and lapse in judgement selecting the right machine and appreciating its quality is key

• Alternative Methods/Innovations should also be considered to increase safety without the need for human interference

Conclusion

Singapore Pest Management Association (SPMA) http://www.spma.org.sg