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-05-06
Date Revised: 04-30-13


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SOP No. EQ-05-06
Date Revised 04-30-13
Page 1 of 4

SOP Number

EQ-05-06

Title

Calibration and Maintenance of Timers

Scope

Describes 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Date SOP withdrawn: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-05-06
Date Revised 04-30-13
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

4

13.

DATA ANALYSIS/CALCULATIONS

4

14.

FORMS AND DATA SHEETS

4

15.

REFERENCES

4


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SOP No. EQ-05-06
Date Revised 04-30-13
Page 3 of 4

1. Definitions

1. ISO = International Organization for Standardization

2. Health and
Safety

None

3. Personnel
Qualifications
and Training

Refer to SOP ADM-04, OPP Microbiology Laboratory Training.

4. Instrument
Calibration

1. Calibration of the timers is performed every two years by an ISO 17025
accredited vendor.

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.	If the vendor determines that a timer is out of tolerance and cannot be
properly calibrated, the timer will be replaced.

2.	Procedures will be consistent with SOP ADM-07, Non-Conformance
Reports.

9. Data

Management

1.	An inventory of timers requiring vendor calibration will be maintained
electronically (Timer Certification Record; see section 14). After each
addition to or deletion from the inventory, a hard copy of the inventory
will be filed in the Timer Calibration Certificates notebook.

2.	Data will be archived consistent with SOP ADM-03, Records and
Archives.

10. Cautions

Timers are removed from service when the calibration expires (two years
from the date of calibration) and are returned to service when recalibration is
completed.

11. Special

Apparatus and
Materials

Timer Specifications:

•	Bench top timers

•	Single action

•	Time in/Time out

•	Cumulative and interval split

•	Reads in hours, minutes, seconds, and hundredths or in decimals

•	Individually serial numbered

•	Calibrated by ISO 17025 accredited vendor


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SOP No. EQ-05-06
Date Revised 04-30-13
Page 4 of 4

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 Calibration

a.	Before the calibration expires, remove the timer from service.

b.	Consult ISO 17025 accredited vendor regarding quote for service,
packing/shipping instructions, and completion of any required forms
prior to shipping timers.

c.	Pack and ship timer to vendor.

d.	Once timer has been recalibrated and shipped back to the laboratory,
complete the Timer Certification Record (section 14), file the
certificate in the Timer Calibration Certificates notebook, and return
the timer to service.

e.	Timers that fail calibration are replaced.

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-05-06 Fl.docx

15. References

Operation manuals for timers located in file cabinet in D-wing.


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