PROCEDURE FOR FUMIGATION OF CLEAN ROOMS

1.0 Formaldehyde Solution 37% (Formalin) sufficient to vapourise about 35 ml of Formalin for each cubic metre of enclosed space.

a) Large stainless steel evaporating pans.

b) Thermostatically controlled hot plates.

c) Small stainless steel canisters with perforated stainless steel lids. Polyurethane pieces.

d) Adhesive tapes

e) Goggles

f) Aseptic area garments, duly sterilized

g) Thermometers

h) Petri dishes with nutrient agar media.

2.0 PRECAUTIONS

2.1 Formalin is a strong irritant and is toxic. Inhalation of formaldehyde gas should be avoided since it cause irritation of the respiratory tract. Contact with the skin should also be avoided.

2.2 When Formalin is being handled, protective clothing inclusive of rubber gloves and goggles must be worn.

Personnel must leave the area being fumigated as soon as possible after placing the pans of Fornalin on the hot plates.

2.1 The area being fumigated must be sealed off and all entrances to the area must be locked. The area should not be re-entered until the fumigation is completed.

2.2 When fumigation is over, personnel should enter in teams of two or more and only after ensuring that all gas has been removed from the area by estimation of the concentration of formaldehyde by means of a Draeger gas detection tube.

2.3 All the stages of fumigation should be supervised by responsible personnel who should be inconstant visual contact with the operator to assist them in the event of any accident.

2.4 All persons coming in contact with for formaldehyde solution must wash their hands and faces thoroughly with soap and water before eating and/or drinking.

3.0 OPERA TIONAL REQUIREMENTS

3.1 Effective fumigation requires a minimum temperature of 25"C and relative humidity of at least 50% for the duration of fumigation.

3.2 The areas being fumigated must be completely shut off from other areas of the plant during fumigation.

3.3 At the end of the fumigation period, the area must be ventilated aseptically in such a way that vapours of formaldehyde are completely exhausted to the atmosphere and are not carried into other , areas of the plant.

3.4 Operators should not re-enter fumigated areas until the level of formaldehyde vapours is reduced to less than the threshold limit valve ( T. L. V. of 2 parts per million.

3.5 Fumigation is best carried out immediately prior to the weekend. The area can then be ventilated over the weekend and so may be safely entered on the next working day.

4.0 PROCEDURE

1. All materials, products and equipment that might be damaged or contaminated by formaldehyde should be removed.

2. The room and remaining equipment should be cleaned ,and disinfected using a suitable disinfectant solution such as a 3% solution of Dettol followed by a 0.5% solution of Savlon.

3. With the help of adhesive tapes, all cracks, crevices and openings from the outside should be sealed off leaving only one door open for personnel to leave the area after placement of the evaporating pans. This door should also be sealed off later, after al] the persons have left the room.

4. All exhaust fans and booster fans, should be shut off and the air in-take port ,and outlet to the atmosphere made up suitably.

5. All ultr,l-violet lights should be shut off.

6. Depending on the size of the room one or more stainless .steel evaporating pans should be placed in the room to be t-umigated.

7. Thermometers should be placed strategically throughout the area in such a way that they can be viewed from outside the area.

8. Inside the filling cabinets, sterile polyurethane pieces impregnated with 6 to 8 drops of formaldehyde and enclosed in the stainless steel canisters should be placed.

9. Taking adequate precautions, the operator should pour sufficient formaldehyde solution into the evaporating pans kept on hot plates. The heating should be switched on.

7. The air-handling system supplying the aseptic area .should be switched off.

The area to be fumigated should be evacuated and the exit door sealed.

12. All the doors should carry the signs "Danger – keep out fumigation in progress.

13. If the temperature of the areas is below 25 C, steam coil heaters or electric coils may be used for preheating the areas to 25"C.

14. The temperature setting of the hot plate should be suitably adjusted and the vapours of formaldehyde should be allowed to slowly diffuse in the areas after ensuring that the main door is sealed. The fumigation should be done for at least 25 hours and the temperature of the area should be recorded at frequent intervals.

15. At the end of 36 hours, the air handling system should be switched on the it should be ensured that fresh air replenishment occurs to the fullest extent.

16. Entry by at least two operators at a time .should be made into the fumigated area and the evaporating pans and hot plates should be removed.

17. The aiir handling system controls should be readjusted to the normal operating cycle.

18. Two or three hours after the removal of the formaldehyde pans the sterile area surfaces should be wiped with a solution of Savlon or any other disinfectant, using sterile sponges.

19. With the ultra – violet lamp circuits switched off, the lamps should be wiped with a 70% solution of isopropyl alcohol. The alcohol should be allowed to evaporate completely and then the lamps should be turned on.

20. Petri dishes containing nutrient agar media should be exposed at various places in the area to monitor the microbial load.