Methods Baseline Inspection and Measurement of Local Exhaust Ventilation (LEV) Systems at Spray Booth in Manufacturing Plant.

to check if the LEV system has been tested by a registered professional engineer after construction and installation to demonstrate that the equipment meets with the designs specification. The test and evaluations were conducted at spray booth number 1 and spray booth number 2 respectively in this company as a future reference in order to compare the performance of overall data related with LEV Systems.

2. Methods

E quipment’s are used in this study such as Thermal, Tachometer, Vane anemometer and measuring tape is used to measure the length and distance. To cover-up the holes on the duct, Adhesive Tape are used. Pitot tube is used for pressure measurements. Clamp Meter to measure current and voltage. Manometer is used for airflow measurements. Selection of testing points for fume hood and canopy hood with individual suction fan, face velocities were measured and where applicable and accessible, duct transport velocities and static pressure measurements. The testing of LEV system was carried out in accordance with the methodology in the handbook of the American Conference of Governmental Industrial Hygienists ACGIH [7] . LEV system is comprised of several components such as the hood, duct, air cleaner, motor fan and stack. Method of measurement refers to ACGIH. The choice of location measurement using the recommended equipment is in component to get the data in determining the efficiency of LEV system. In testing procedure, a sketch of the LEV and its associated components was drawn indicating the shape and position of the hood and location of fanmotor and air cleaner.Visual inspection for suitability of hoods, connections between hoods and ducts, obstruction of hoods, position of hoods and workers breathing zones, denting, corrosions, damages to hoods, fans and air cleaners and conditions of work areas.Smoke tube tests carried out at hoods, to determine the dispersion of contaminants, effectiveness, capture distance and cross drafts on hood performance. Conducting smoke tube tracer tests are to evaluate dispersion of contaminants by blowing the smoke at the source of the contaminants and observing the dispersion. Smoke tube will help to identify the point where the initial velocity of contaminants away from the hood is dissipated, determine the effect of cross drafts on hood performance, and finally to locate and study turbulence around openings, spillage and leakage at the hood Duct velocity pressure measurements were taken at suitable points along the duct to determine the transport velocity, volumetric flow rate in the duct. Small holes of 38 inches diameter are drilled at traverses across the diameter of duct at right angle to each other. Whenever possible, the traverses are made at distance of 7.5 diameters or more downstream from any major air disturbance such as an elbow, hood, branch entry etc. If measurements are made closer to disturbances, the results will be considered subject to some doubts and re-checked at a second location. If agreement within 10 of the two traverses is obtained, reasonable accuracy can be assumed and the average of the two readings is used. A third location is selected only if the variation exceeds 10 and the two airflows in the best agreement is averaged and used as the result. Velocity pressure was measured at various points over a number of equal areas in the cross section of the duct. The average velocity measured was used to determine the transport velocity at the point of the duct. Duct static pressure measurements points were similar to that of the velocity pressure measurements. The measurement could be used to measure performance and to diagnose any malfunction. The locations of measurements chosen were at entries of branch into main duct, on each side of air cleaners, on each side of fan and at several points along ducts. The actual points chosen for measurements were indicated as in the relevant appendices.Inlet and outlet static pressure of the air cleaners were determined by using Pitot tube and anemometer.The fan rpm and the staticvelocity pressure were measured before and after the fan by using Tachometer, Pitot tube and Anemometer.

3. Case Study Description