Primary_Barrier_Exhibit_Protocol.CFH_.doc

CERTIFICATION OF CHEMICAL FUME HOODS

The purpose of this standard is to establish the chemical fume hood certification procedure that shall be followed by the NIH primary barrier certification contractor at all NIH facilities.

1. Standards for Chemical Fume Hood Evaluation a.

Physical condition and defects in the following features are to be observed and appropriately documented.

(1) Overall general physical condition of the fume hood.

(2) Holes or cracks in the bench top.

(3) Obstruction of the back slots by equipment or materials in the fume hood.

(4) Clutter and obstructions at the hood face, either from objects inside toward the front or outside the hood (such as furniture, refrigerators, etc.).

(5) Condition of sash: are there cracks in the glass; are the seals in place; does the sash move freely; or does the sash stick or creep down?

b.

Air Flow Measurements

(1) The measuring instrument used shall:

(a) Be a calibrated thermo-anemometer that has been approved by the Project Officer.

(b) Be capable of measuring velocities from 25 feet per minute to 300 feet per minute. Measurements shall be accurate to within +/-5% of each measurement.

(c) Be calibrated and certified every six months, or more often if such action is necessary during the contract period, by a qualified independent laboratory.

(2) Measure airflow through the face of each hood in linear feet per minute (fpm) and later use the average to calculate the cubic feet per minute (cfm). Minimum face velocity average is 100 fpm with a minimum sash opening of eight inches. No individual measurement shall be less than 80 fpm. The average face velocity should not exceed 140 fpm. When initially certifying a new hood, measure the sash height at approximately 18". Raise or lower sash as needed to certify the hood. Also, on a new hood, if the sash must be adjusted more than two inches from the 18" setting, notify the Project Officer.

(3) Using a thermo-anemometer, take face velocity readings by holding the probe on a plane made by the bottom of the sash and the work-surface. In a four foot hood, take two readings (one on each side of the hood) 4" from the side of the hood and 4" from the bottom of the sash. Take two other readings, one on each side, 4" from the side of the hood and 4" above the work-surface. Also, take readings in the middle of the hood, one 4" from the bottom of the sash and the other 4" above the work-surface. Take a total of six readings.

In a six foot hood, with the same distances from the sides and same distances from the bottom of the sash and above the work surface (as described for the four foot hood), take two readings on each side and four readings equidistant between the middle of the hood and the locations where the side readings were taken, for a total of eight readings.

If the sash is set at a height of 20" or more, take an additional row of readings across the face of the hood in the center.

Do not take readings in front of large instruments that are toward the front of the hood (probe should be moved to avoid this).

(4) After the sash height is established, use a smoke source. If the smoke pattern is acceptable, i.e., smoke captured without demonstrating turbulence or any escaping of smoke, certify the hood.

(5) Date and initial new labels and place the Recommended Sash Height sticker at the proper sash height (green background; see Attachment, Figure 1). Remove from the hood all old certification stickers.

(6) Label all hoods that do not meet requirements of Para. (2) above or have sashes that cannot be lowered all the way down to the air foil with a Failed Certification sticker (Attachment, Figure 1) and place the sticker in the middle of the glass sash. Remove any other existing hood labels pertaining to the sash height. Initial and date the sticker. By phone, immediately report failures to the Project Officer.

(7) On the service reports, note hoods that are being used with perchloric acid.

(8) In certain locations, there are special-purpose chemical fume hoods that have different requirements. Refer to the comment section of the computer printout, which lists the chemical fume hoods by building and room number, before certification so these requirements can be noted. (For example, in Building 10, ACRF, first floor in Nuclear Medicine, a smoke pencil is not to be used in one of the hoods due to product protection.)

(9) When results are marginally passing, and velocity readings have been taken with the laboratory door or doors open to the corridor, retest with the doors closed to ensure the hood will pass under these conditions (velocities tend to lower with doors closed). If the hood doesn't meet all the criteria for passing, place a "Failed, Do Not Use" sticker on the hood, as described above.

2.

Procedures for Making Survey The annual survey of chemical fume hoods shall be conducted as follows:

a.

Enter information from the service report which is used to collect the data into the NIH database.

b.

If the hood to be certified is a new hood, fill out the description of the chemical fume hood, location, and other pertinent information on the service report.

c.

Inspect the hood for physical defects and note them in the comment section of the service report.

d.

Measure velocities at the present sash setting. If measurements meet the criteria to pass, record sash height and velocities on the service report.

e.

If the sash needs to be adjusted, do so until the velocities and the height of the sash meet the standards found in this document under "Air Flow Measurements" and place proper signage on the hood.

f.

If the hood fails, indicate this on the report and why and place the proper signage on the hood. Immediately report failures to the Project Officer by phone, and have lab personnel sign the service report and acknowledge that the hood has failed and is not to be used.

g.

Upon completion of each day's survey, submit the completed service reports the next work day to the Project Officer.

3.

Report of Work Report to the Project Officer on a daily basis on the deficiencies and other pertinent information concerning hoods.

4.

Trouble Calls

These calls are from lab personnel or Office of Research Facilities, NIH, requesting the need of a certification of a new chemical fume hood or a re-certification. The NIH contractor shall respond to such calls.