SOP For Operation of Laminar Flow-Hood is described in this post which you can follow in the section of microbiological lab. 

Objective:

This procedure has been established for operation of laminar flow-hood in controlled environment of sterile manufacturing area and sterile testing area i.e. (Microbiology Lab).

Scope:

This procedure is applicable to the sterile area (Manufacturing & Microbiological Testing Lab).

Responsibility:                                

Microbiologist.

Sterile Area Pharmacist.

Microbiology Lab Attendant.

Accountability:

Quality Control Manager. 

Procedure:

First of all follow the proper gowning procedure to enter the microbiology testing area 

disinfect the hands with 70% IPA (Isopropyl Alcohol). 

Switch "ON" the main supply of the LFH.

Turn "ON" the tube light and "OFF" the UV light of the LFH.

Do not on the normal tube light and UV light simultaneously.

Turn "ON" the blower/fan and Observe the differential pressure on Megnahelic gauge provided on LFH

At the end switch "OF" tube light, blower/fan and UV-Light.

Immediately after exit from area record the UV-life-hours and differential pressure in the respective logbooks.

Eternal Validation of LFH  Includes (PAO (Poly Alpha Olefin) test, Air velocity, and particle count atleast once in a year is mandatory.

Frequency Of External Validation for HEPA Filter of LFH: Once in a year

Standard UV Light life hours: 6000 hours.

Acceptance Limits for Differential pressure: 

According to WHO: 10-15 Pascal's between the adjacent areas.

According to USP: 05-12.45 Pascal's between the adjacent areas.

According to ISO: 05-20 Pascal's between adjacent areas.

If the differential pressure observed is not satisfactory or out of range then intimate the engineering department for its maintenance.