US Environmental Protection Agency
Office of Pesticide Programs
Office of Pesticide Programs
Microbiology Laboratory
Environmental Science Center, Ft. Meade, MD
Standard Operating Procedure for
Calibration and Maintenance of Timers
SOP Number: EQ-05-08
Date Revised: 08-07-19

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SOP No. EQ-05-08
Date Revised 08-07-19
Page i of 4
SOP Number
EQ-05-08
Title
Calibration and Maintenance of Timers
Revisions Made
•	Added the option of replacing timers when their ISO accreditation
expires with newly purchased and accredited timers.
•	Minor editorial changes.

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SOP No. EQ-05-08
Date Revised 08-07-19
Page 1 of 4
SOP Number
EQ-05-08
Title
Calibration and Maintenance of Timers
Scope
Describes the process for calibration and maintenance of timers,
certified instruments that can display time in seconds.
Application
Timers are used for managing timed activities in test methods.


Approval Date
SOP Developer:

Print Name:
SOP Reviewer

Print Name:
Quality Assurance Unit

Print Name:
Branch Chief

Print Name:


Date SOP issued:

Controlled copy
number:

Date SOP withdrawn:

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SOP No. EQ-05-08
Date Revised 08-07-19
Page 2 of 4
TABLE OF CONTENTS
Contents	Page Number
1.
DEFINITIONS
3
2.
HEALTH AND SAFETY
3
3.
PERSONNEL QUALIFICATIONS AND TRAINING
3
4.
INSTRUMENT CALIBRATION
3
5.
SAMPLE HANDLING AND STORAGE
3
6.
QUALITY CONTROL
3
7.
INTERFERENCES
3
8. NON-CONFORMING DATA
3
9.
DATA MANAGEMENT
3
10.
CAUTIONS
3
11.
SPECIAL APPARATUS AND MATERIALS
3
12.
PROCEDURE AND ANALYSIS
3
13.
DATA ANALYSIS/CALCULATIONS
4
14.
FORMS AND DATA SHEETS
4
15.
REFERENCES
4

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SOP No. EQ-05-08
Date Revised 08-07-19
Page 3 of 4
1. Definitions
1.	A2LA = American Association for Laboratory Accreditation
2.	ISO = International Organization for Standardization
3.	NVLAP = National Voluntary Laboratory Accreditation Program
2. Health and
Safety
None
3. Personnel
Qualifications
and Training
Refer to SOP ADM-04, OPP Microbiology Laboratory Training.
4. Instrument
Calibration
Not applicable
5. Sample
Handling and
Storage
Not applicable
6. Quality Control
For quality control purposes, the required information is documented on the
appropriate form(s) (see section 14).
7. Interferences
None
8. Non-
conforming
Data
1. Procedures to handle non-conformances are consistent with SOP ADM-
07, Non-Conformance Reports.
9. Data
Management
1. Data will be archived consistent with SOP ADM-03, Records and
Archives.
10. Cautions
Not applicable
11. Special
Apparatus and
Materials
Timer Specifications:
•	Battery operated bench top timers
•	Reads in hours, minutes, and seconds
•	Individual serial numbers
•	Calibrated per ISO 17025
12. Procedure and
Analysis
Calibration certificates must contain the stamp of the accrediting body (e.g.,
A2LA, NVLAP) and the calibration vendor certificate number.
12.1 Use Period of
Timers
a.	Purchase new timers with accredited calibration certificates.
b.	Maintain an electronic inventory of timers with their calibration
certification (Timer Certification Record; see section 14). Enter the
timer serial number and calibration expiration date into the electronic
inventory. After each addition, file a hard copy of the inventory and
calibration certificate in the Timer Calibration Record notebook.

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SOP No. EQ-05-08
Date Revised 08-07-19
Page 4 of 4

c. When the calibration expires, remove the timer from service and the
inventory.
12.2 Operation
Follow the instructions, provided by the manufacturer, for the operation of
each timer. See section 15.
13. Data Analysis/
Calculations
None
14. Forms and Data
Sheets
Form is stored separately from the SOP under the following file name:
Timer Certification Record EQ-05-08 Fl.docx
15. References
Operation manuals for timers located in file cabinet in D-wing.

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