What Breathalyzer Calibration Records Show
A breath result is only as good as the instrument that produced it. Breathalyzer calibration records show how often the device was checked against a known alcohol sample and whether it stayed within limits. Lawyers review them because state rules set specific standards.
Those rules appear in Title 17 section 1221.2 of the California Code of Regulations. They cover the samples, the accuracy checks, operator training and record keeping.
What the Accuracy Rules Require
Each evidential test includes two separate breath samples. The two results must not differ by more than 0.02 grams per 210 liters of breath.
The instrument also needs periodic accuracy checks against a reference sample of known concentration. Each check must fall within plus or minus 0.010 of the true value, and “periodic” means at least every 10 days or after every 150 subjects, whichever comes sooner.
Records Each Instrument Must Have
Section 1221.2 requires records for each instrument showing how often staff checked its accuracy. It also requires records naming anyone who performed a manual check. A forensic alcohol laboratory keeps records showing compliance.
So breathalyzer calibration records usually come from two places, the agency and the lab. A request often asks for both.
- Accuracy check logs before and after the test date
- Reference sample details
- Operator training certificates
- Maintenance and repair notes
Operator Training Records
An operator must complete training that includes theory, the instrument procedure, a precautionary checklist and a hands on test. Training also covers the required 15 minute wait period. A certificate shows the operator’s name and agency.
Reviewers compare that certificate with the name on the test printout. A mismatch raises questions worth asking.
How Breathalyzer Calibration Records Get Requested
Once a case is filed, a defense lawyer asks for these records in discovery. The guide on DUI criminal discovery explains that process. Vehicle Code section 23158 also says full information about a test taken at an officer’s direction must be available to the person or the person’s lawyer on request.
For the DMV hearing, the timeline is shorter. The article on DMV DUI hearing evidence covers what to request there.
What a Gap Can and Cannot Mean
A missed check or a late entry does not automatically erase a result. Still, it can weaken the weight a court or hearing officer gives to it. An expert may explain what a gap means for a specific test.
The article on DUI forensic expert reviews describes what such a reviewer does with breathalyzer calibration records and related logs.
The article on mouth alcohol DUI issues explains why the observation period matters.