Test atmospheres A。, A20, and Aso shall be consistent during the tests and from day to day.

(ii) For steps (xxv) through (xxxi) of this section, a chart speed of at least 10 centimeters per hour shall be used. The actual chart speed, chart speed changes, and time checks shall be clearly marked on the chart.

(iii) Allow sufficient time for test analyzer to warm up and stabilize at a line voltage of 115 volts and a room temperature of 25° C. Recalibrate, if necessary, and adjust the zero baseline to 5 percent of chart. No further adjustments shall be made to the analyzer until the end of the tests on the third day.

(iv) Measure test atmosphere A. until a stable reading is obtained, and record this reading (in ppm) as Zn where n=0 (see Figure B-4 in Appendix A).

(v) Measure test atmosphere A20. Allow for a stable reading and record it as M'n, where n=0.

(vi) Measure test atmosphere Aso. Allow for a stable reading and record it as S', where n=0.

(vii) The above readings for Z'o, M'o, and S. should be taken at least four (4) hours prior to the beginning of test day 1.

(viii) At the beginning of each test day, adjust the line voltage and room temperature to the values given in Table B-4.

(ix) Measure test atmosphere A。 continuously for at least twelve (12) continuous hours during each test day.

(x) After the 12-hour zero drift test (step ix), sample test atmosphere A。. A stable reading is not required.

(xi) Measure test atmosphere A20 and record the stable reading (in ppm) as P1. (See Figure B-4 in Appendix A.)

(xii) Sample test atmosphere Ao; a stable reading is not required.

(xiii) Measure test atmosphere A20 and record the stable reading as P2.

(xiv) Sample test atmosphere A.; a stable reading is not required.

(xv) Measure test atmosphere A 20 and record the stable reading as P1. (xvi) Sample test atmosphere A; a stable reading is not required.

(xvii) Measure test atmosphere Azo and record the stable reading as P..

(xviii) Sample test atmosphere A.; a stable reading is not required.

(xix) Measure test atmosphere A and record the stable reading as Ps. (xx) Sample test atmosphere A; a stable reading is not required.

(xxi) Measure test atmosphere Ax and record the stable reading as P.. (xxii) Measure test atmosphere Aso and record the stable reading as P,. (xxiii) Sample test atmosphere A0; a stable reading is not required.

(xxiv) Measure test atmosphere Ase and record the stable reading as P.. Increase chart speed to at least 10 centimeters per hour.

(xxv) Measure test atmosphere A.. Record the stable reading as L1.

(xxvi) Quickly switch the test analyzer to measure test atmosphere A.. and mark the recorder chart to show the exact time when the switch occurred.

(xxvii) Measure test atmosphere As and record the stable reading as Pso. (xxviii) Sample test atmosphere A90; a stable reading is not required.

(xxix) Measure test atmosphere Aso and record the stable reading as P10. (xxx) Measure test atmosphere A. and record the stable reading as L2. (xxxi) Measure test atmosphere Aso and record the stable reading as P11. (xxxii) Sample test atmosphere A,.; a stable reading is not required.

(xxxiii) Measure test atmosphere Ase and record the stable reading as P12. (xxxiv) Repeat steps (viii) through (xxxiii) of this section, each test day.

(xxxv) If zero and span adjustments are made after the readings are taken on test days 3, 6, 9, or 12, complete all adjustments; then measure test atmospheres A., Aso, and A20. Allow for a stable reading on each, and record the readings as Z'n S'n, and M, respectively, where n the test day number.

(10) Determine the results of each day's tests as follows. Mark the recorder chart to show readings and determinations.

(i) Zero Drift. (A) 12-hour. Examine the strip chart pertaining to the 12hour continuous zero air test. Determine the minimum (Cmin.) and maximum (Cmax.) readings (in p/m) during this period of 12 consecutive hours, extrapolating the calibration curve to negative concentration units

(B) Calculate the 24-hour zero drift (24ZD) for the n-th test day as 24 ZDn=Zn-2-1, or 24ZDn=Zn-Z'n-1 if zero adjustment was made on the previous day, where Z1 = 1⁄2 (L1+L2) for L and L2 taken on the n-th test day.

(C) Compare 12 ZD and 24 ZD to the zero drift specification in Table B-1. Both 12 ZD and 24 ZD must be equal to or less than the specified value to pass the test for zero drift.

n indicates the n-th test day, and i indicates the i-th reading on the n-th test day.

(C) Both USD and MSD must be equal to or less than the respective specifications given in Table B-1 to pass the test for span draft.

(iii) Lag Time. Determine, from the strip chart, the elapsed time in minutes between the mark made in step (xxvi) and the first observable (two times the noise level) response. This time must be equal to or less than the time specified in Table B-1 to pass the test for lag time.

(iv) Rise Time. Calculate 95 percent of reading P, and determine from the recorder chart, the elapsed time between the first observable (two times noise level) response and a response equal to 95 percent of the P, reading. This time must be equal to or less than the rise time specified in Table B-1 to pass the test for rise time.

(v) Fall Time. Calculate five percent of (P10-L2) and determine, from the strip chart, the elapsed time in minutes between the first observable decrease in response following reading PIO and a response equal to five percent of (P10-L2). This time must be equal to or less than the fall time specification in Table B-1 to pass the test for fall time.

10

(vi) Precision. Calculate precision (P20 and PSO) for each day's test as follows:

(A)

or

(B)

S-1

if span adjustment was made on the previous day, where

(C) Both P20 and PRO must be equal to or less than the specification given in Table B-1 to pass the test for precision.

[40 FR 7049, Feb. 18, 1975, as amended at 41 FR 52694, Dec. 1, 1976]