Calibrations–Part 60 vs 75

Calibrations are an integral part of operating a CEM system effectively. However, depending on which regulations your site falls under, this process can be subject to different requirements. It is crucial that you understand these differences, especially if you are a site that is subject to both regulations, in order to maintain compliance and minimize downtime. Below are important ways in which Part 60 calibrations differ from Part 75 calibrations.


Drift Specifications


 Part 60Part 75
NOx2.5% span5% span OR 5ppm (if range <50ppm) OR 10ppm (if range >50<200ppm)
SO22.5% span5% span OR 5ppm (if range <50ppm) OR 10ppm (if range >50<200ppm)
CO5% spanNone
NH32.5% spanNone
O20.5% span1%
CO20.5% span1%
Velocity3% span6%
Opacity2% spanNone

*References: 40CFR60 App_B Spec 1-4; 40CFR75 App_B § 2.1.4


Out of Control Criteria


 Part 60Part 75
Single Failed Cal4x drift spec. in a single calibration1x drift spec. in a single calibration
5 Day Drift Limit5th consecutive cal at 2x drift spec. is OOCNone

*References: 40CFR60 App_F § 4.3.1; 40CFR75 App_B § 2.1.4

Data Invalidation


 Part 60Part 75
Failed CalibrationOOC back to last passing cal until next passing calOOC from failed cal until next passing cal
Missed CalibrationAfter approximately 24 hours, data is OOC until next passing calAfter 26 hours, data is OOC until next passing cal

*References: 40CFR60 app. F § 4.3.1; 40CFR75 app. B § 2.1.5


Daily Calibration Hourly Requirements

 Part 60Part 75
Daily CalibrationApproximately every 24 hoursEvery 26 hours
Grace PeriodNone8 hours after startup**

*References: 40CFR60 App_F § 4.1; 40CFR 75 App_B § 2.1.5

**several requirements apply for this exception


Range Requirements


 Part 60Part 75
Zero0-20% span0-20% span
MidNone50-60% span
High50-100% span80-100% span (can use mid in lieu of high if more representative)

*References: 40CFR60.13.d; 40CFR75 App_A § 5.2



As always, if you have questions on which requirements apply to your facility and what that means for you, feel free to contact us.