---
kind: "section"
citation: "40 C.F.R. § 63.9921"
title: "40"
number: "63.9921"
heading: "What are the installation, operation and maintenance requirements for my monitors?"
url: "https://uscodex.org/cfr/40/63.9921"
---

# §63.9921. What are the installation, operation and maintenance requirements for my monitors?

- (a) For each wet scrubber subject to the operating limits in [§ 63.9890(b)](/cfr/40/63.9890.md?p=b) for pressure drop and scrubber water flow rate, you must install, operate, and maintain each CPMS according to the requirements in paragraphs [(a)(1)](#a-1) and [(2)](#a-2) of this section.
  - (1) **For the pressure drop CPMS, you must—**
    - (i) Locate the pressure sensor(s) in or as close to a position that provides a representative measurement of the pressure and that minimizes or eliminates pulsating pressure, vibration, and internal and external corrosion.
    - (ii) Use a gauge with a minimum measurement sensitivity of 0.5 inch of water or a transducer with a minimum measurement sensitivity of 1 percent of the pressure range.
    - (iii) **Check the pressure tap for pluggage daily.**
    - (iv) **Using a manometer, check gauge calibration quarterly and transducer calibration monthly.**
    - (v) Conduct calibration checks any time the sensor exceeds the manufacturer's specified maximum operating pressure range, or install a new pressure sensor.
    - (vi) At least monthly, inspect all components for integrity, all electrical connections for continuity, and all mechanical connections for leakage.
  - (2) **For the scrubber water flow rate CPMS, you must—**
    - (i) Locate the flow sensor and other necessary equipment in a position that provides a representative flow and that reduces swirling flow or abnormal velocity distributions due to upstream and downstream disturbances.
    - (ii) **Use a flow sensor with a minimum measurement sensitivity of 2 percent of the flow rate.**
    - (iii) Conduct a flow sensor calibration check at least semiannually according to the manufacturer's instructions.
    - (iv) At least monthly, inspect all components for integrity, all electrical connections for continuity, and all mechanical connections for leakage.
- (b) You must install, operate, and maintain each CPMS for a wet scrubber according to the requirements in [paragraphs (b)(1) through (3)](#b-1..b-3) of this section.
  - (1) Each CPMS must complete a minimum of one cycle of operation for each successive 15-minute period.
  - (2) Each CPMS must have valid data for at least 95 percent of every averaging period.
  - (3) Each CPMS must determine and record the hourly average of all recorded readings.

## Notes

### Source

Source: 68 FR 58620, Oct. 10, 2003, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Source

Source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.