PID

1. Simple: PID reading x CF = Actual PPM present of chemical.

2. Entry team turn around: Desired reading (e.g. IDLH) on PID ÷ CF = Reading on the PID.

3. Entry team turn around based on desired LEL:  Desired reading (e.g. 25% LEL). PLEL% x 10,000 ÷ 25 = 25% LEL in PPM. Use this number and ÷ CF = PID reading PPM for 25% LEL.

4. Predicted PID (1300): 1300 Rule gives predicted PPM ÷ CF = Predicted maximum PID reading.

%O2

5. O2 displacement in PPM: 20.9% minus (-) actual reading in % x 5 x 10,000 = PPM.

6. Predicted O2 reading (1300): 1300 Rule gives predicted PPM ÷ 50,000 = % O2 drop from 20.9%.

7. O2 sensor can only measure to 0.1% (1,000 PPM) and is 1/5 of total displacement.  0.1% x 5 = 0.5% (5,000 PPM).  Therefore: for every 0.1% drop from 20.9% = 5,000 PPM drop in total air.  NOTE: O2 can also be consumed, this would not follow teh rule of 5ths, because the N2 remains.

LEL

8. Simple: LEL meter reading x CF = Actual LEL.

9. Entry team turn around: Desired LEL reading (e.g. 25%) ÷ CF = Actual LEL meter reading.

10. PPM conversion: LEL reading x CF x PLEL% ÷ 100 x 10,000 = PPM.

11. Predict LEL reading (1300):1300 Rule gives predicted PPM = (X).

(CF x PLEL x 100) = (Y)

(X) ÷ (Y) = Predicted LEL Reading