Quality System Procedure - Equipment

Most recently edited by: Ryan Smothers
Most recent edit date: Jan 17th, 2023
Edits were authorized by: Paul VanderWeele

References

EPA 815-R-05-004, Manual for the Certification of Laboratories Analyzing Drinking Water, Criteria and Procedures Quality Assurance, 5th Ed., U.S. Environmental Protection Agency, January 2005
EPA 815-F-08-006, Supplement 1 to the Fifth Edition of the Manual for the Certification of Laboratories Analyzing Drinking Water, Supplement 1 to EPA 815-R-05-004, U.S. Environmental Protection Agency, June 2008
AOAC International, Guidelines for Laboratories Performing Microbiological and Chemical Analyses of Food, Dietary Supplements, and Pharmaceuticals, An Aid to Interpretation of ISO/IEC 17025:2017, AOAC International, August 2018
ISO/IEC 17025(E), General requirements for the competence of testing and calibration laboratories, 3rd Ed., November, 2017.

Scope and Purpose

The purpose of this procedure is to define proper laboratory equipment management by defining the requirements for handling, transport, storage, calibration, verification, maintenance, and safeguards for onsite equipment. Additionally, equipment outside the laboratory's permanent control that is used to produce results that will be reported by the laboratory shall be managed with a program commensurate to the program detailed herein.

The requirements included in this document are based upon the current laboratory certifying bodies, EGLE and AOAC, and represent minimum compliance to these certifications. Additional equipment / method controls may be established in equipment / method SOPs above and beyond these requirements to ensure validity of laboratory reported values but any decision to perform less than the requirements of this document should be considered a deviation. Deviations must be approved by either the Quality Assurance Officer or Technical Director and should be documented to include the nature of the deviation, justification, samples affected, approval, and date. Deviation documentation must be retained as a record for a period of time equivalent to any affected sample's record retention requirements. If the laboratory certifying bodies change this procedure should be revised to ensure compliance with the new certification requirements.

Terms and Definitions

See Quality System Manual - Terms and Definitions

Equipment Handling Storage and Transport

Equipment shall be handled in accordance with manufacturer instructions. Special handling instructions should be included in the equipment's related standard operating procedure.

Equipment should be stored in the proper working environment as defined by equipment vendor manuals. When new equipment is placed in service, equipment vendor manuals should be reviewed for storage requirements. These storage requirements should be added to the equipment SOP and adhered to unless technical justification is documented.

Equipment calibration / function may be affected by equipment transport. Sensitive equipment (e.g., balances) should not be moved from their place of calibration. When transporting equipment, ensure care is taken to minimize potential for equipment damage and personnel injury. Post-transport, equipment should not be used unless all method specific quality control verifications are performed and within acceptable limits (see Equipment Verification).

Equipment Calibration

Equipment calibrations shall be conducted in accordance with the established method using standards with the appropriate traceability.

Typically, calibrations will include a minimum of at least 3 calibration points for linear calibrations and 5 calibration points for non-linear calibrations. The type of calibration and points used for calibration should align with the testing performed for method validation and the approved operating procedure for that method.

Calibrations shall be evaluated for accuracy upon completion. Unless otherwise justified through the method validation process, satisfactory calibration will exhibit a correlation coefficient >= 0.995. Additionally, some method SOP's may require other post-calibration verifications such as back-calculating individual calibration response data to ensure the best-fit line is within acceptance criteria (e.g., <=10%)

New equipment calibrations should not be used unless all method specific quality control verifications are performed post-calibration and within acceptable limits (see Equipment Verification).

Equipment Verification

Equipment verification received upon receipt of new equipment should be saved as part of, or the start of, the equipment history log. Ongoing equipment verification performed by the vendor should also be documented in the equipment history log.

Complex equipment is not typically verified by laboratory personnel. Rather, individual methods on complex equipment are validated separately. Initial and ongoing method validation requirements are described in QSP-Methods

Other equipment verifications performed by laboratory personnel are described in Specific Equipment Requirements

Equipment Maintenance

Equipment maintenance should be performed at the manufacturer's recommended periodicity or regulatory document's recommended periodicity whichever is shorter unless technical justification is documented.

Equipment maintenance, both preventative and corrective, shall be documented in an equipment specific maintenance log. The maintenance log should detail, at a minimum, the maintenance performed, date, and individual performing the maintenance. The maintenance log should include additional information as described in Specific Equipment Requirements. This log should contain both maintenance performed by laboratory personnel and visitors performing maintenance.

See Specific Equipment Requirements for details of required maintenance and frequency.

Equipment Safeguards

Equipment used to produce analytical results undergo validation testing to ensure method performance meets business and customer needs. The process of validation testing determines optimal settings for equipment operation. Modification of equipment settings and operation of equipment outside validated parameters may cause degraded equipment performance that no longer meets business and customer needs. To prevent such occurrences, equipment settings should not usually be modified and equipment should not be used to produce results outside of the established method validation parameters. Minor adjustments to equipment parameters as correction to component wear are permitted.

The main safeguard against equipment modification is the use of standard operating procedures (SOPs). SOPs describe how to operate equipment and will describe parameters that may be adjusted, any quality control validations post-adjustment, and acceptance criteria. Based on observations during method validation, SOPs are written to prevent equipment adjustments that will negatively impact sample results or such that adjustments are validated to not negatively impact sample results prior to reporting. Generally, when SOPs are adhred to, equipment and method performance will continue to meet business and customer needs without the need to perform additional in-depth validation testing.

Major equipment maintenance / repair should be evaluated for potential to invalidate method validation testing. Any initial tests that may have been affected should be retested in accordance with QSP-Methods

Where modification to equipment that may have significant impact on equipment/method performance are easily accessible the laboratory should consider additional controls to prevent such modification.

Specific Equipment Requirements

Autoclave

The autoclave should have an internal heat source, a temperature gauge with a sensor on the exhaust, a pressure gauge, and an operational safety valve. The autoclave should maintain a sterilization temperature during the sterilizing cycle and complete an entire cycle within 45 minutes when a 12-15 minute sterilization period is used. The autoclave should depressurize slowly enough to ensure that media will not boil over and bubbles will not form in inverted tubes.

Pressure cookers should not be used for sterilization.

Each time the autoclave is used, the date, contents, sterilization time and temperature, total time in the autoclave, and analyst's initials should be recorded. A maximum-temperature-registering thermometer, electronic temperature readout device, or continuous recording device should be used during each autoclave cycle to ensure that the proper temperature was reached, and the temperature recorded. Overcrowding should be avoided. Note that chemical indicators (e.g., autoclave tape) will respond to a wide range of times and temperatures (e.g., longer time lower temperature or shorter time higher temperature). Therefore, chemical indicators should not be used to show that sterilization has occurred. Door seals should be clean and free of carmelized media.

Weekly: Spore strips or spore ampules should be used as bioindicators to confirm sterilization. Autoclave drain screens should be cleaned frequently and debris removed.

Quarterly: Automatic timing mechanisms should be checked with a stopwatch or other accurate timepiece and the results recorded.

Annually: Verify the accuracy of the temperature sensing system. Verify uniformity of temperature by documenting temperature in different regions of the autoclave. Service contract work and maintenance records shall be maintained.

Automated Colony Counter

Annually: Verify the accuracy against a manual count and document results.

Balance

Balances should have readability of 0.1g if used for microbiological drinking water analysis and 0.0001g if used for chemical drinking water analysis.

Daily when in use: Balances should be verified using at least three ASTM Class 1, 2, or 3 non-reference weights. For balances used for microbioligical drinking water analysis, a sensitivity check should be performed by adding a 0.1g weight to the upper check point.

Annually, when moved to a new location, or after repair: Maintenance, calibration, and cleaning should be conducted at least annually by a qualified independent technician. Calibrations should be performed using ASTM Type 1, Class 1 or 2 weights.

Colorimetric Devices

Colorimetric devices include spectrophotometers or any piece of equipment using a spectrophotometer detector (e.g., Thermoscientific Gallery Plus)

Daily when in use: Verify blank reading. Document results and any abnormalities noted. The Gallery Plus equipment is in essence an automated colorimetric device. The Gallery Plus performs an automatic blank subtraction but does not allow access to the observed blank value therefore the blank reading does not need to be documented daily for this device.

Annually: Wavelength settings on spectrophotometers should be verified at least annually with color standards and records retained with the equipment's maintenance log and be available for inspection.

Conductivity Meter

Meter must be suitable for checking reagent-grade water and readable in units of µmho/cm or µS/cm.

Monthly: Calibrate at least monthly following manufacturer's recommendations and using an appropriate certified and traceable low-level standard (<20µmho/cm). If the meter cannot be calibrated at least monthly then the cell constant should be determined monthly in accordance with Standard Methods 2510. Calibrations should be recorded in the equipment maintenance log. If an inline conductivity cell cannot be calibrated it should no be used to check reagent grade water.

Glassware / Plasticware

Glassware used for microbiological drinking water analyses should be borosilicate glass or other corrosion-resistant glass and free of chips and cracks. Markings on graduated cylinders and pipets must be legible. Plastic items should be clear and non-toxic to microorganisms.

Graduated cylinders for measurement of sample volumes must be accurate to within a 2.5% tolerance. In lieu of graduated cylinders, precalibrated containers that have clearly marked volumes accurate to within a 2.5% tolerance may be used.

Culture tubes and containers containing fermentation medium should be of sufficient size to contain medium plus sample without being more than three quarters full.

Upon receipt: For pipets, burets, and volumetric flasks obtained without class A certification, verify the accuracy using mass of water at a known temperature. Spectrophotometric method may be used for extremely low volumes.

Prior to use: Glassware used for microbiological analysis should be cleaned prior to use with a cleaning agent such as Alconox or equivalent. pH should be verified post-cleaning with 0.04% Bromothymol Blue and reagent grade water as follows: 1. Fill glassware 1/2 full with reagent grade water. 2. Swich water around the glassware to extract any residues off the sides 3. add 2-3 drops of 0.04% Bromothymol Blue and observe the color. 4. A pale blue color is a failing reading indicative of an alkaline residue 5. A blue/green color is inidicative of a passing neutral pH 6. A yellow color can be considered passing if the reagent water is pH 5.50-6.50

Hydrometer

Annually: Verify all working hydrometers against the NIST traceable reference hydrometer.

Every 2 years: Recalibrate the NIST traceable reference hydrometer.

Incubator Unit

Incubator units must have an internal temperature monitoring device and maintain the temperature specified by the method used, usually 35+/-0.5°C and 44.5+/-0.2°C. For non-portable incubators, thermometers should be placed on the top and bottom shelves of the use area and immersed in liquid as directed by the manufacturer (except for electronic thermometers).

Daily or 2x/Day when in use: Calibration-corrected temperature should be recorded daily (twice per day with at least 4 hours between readings for microbiological drinking water analysis) for each incubator in-use. Documentation must include the date, time, temperature, and technician's initials.

pH Meter

Accuracy and scale graduations should be within +/-0.10 pH units. pH buffer aliquots should be used only once for drinking water analyses. Electrodes should be maintained according to manufacturer recommendations

Commercial buffer solution containers should be dated upon receipt and when opened. Buffers should be discarded by the expiration date.

Daily prior to use: Standardization should be performed daily prior to use with buffers bracketing the expected range of sample analysis. The date, analyst, buffers used, and pH meter slope should be recorded in the equipment maintenance log. If the pH slope is outside 95% to 105% the electrode may need maintenance. Follow manufacturer's instructions.

Pipets

To sterilize and maintain sterility of glass pipets, stainless steel or aluminum canisters should be used, or individual pipets should be wrapped in char-resistant paper or aluminum foil. Opened packs of disposable sterile pipets should be resealed between use periods. Calibrated micropipetters may be used for microbiological drinking water analysis if tips are sterile. Pipets delivering volumes of 10 ml or less must be accurate to within a 2.5% tolerance if used for microbiological drinking water analysis.

Pipets should have legible markings and should not be chipped or etched.

Every 6 months and upon receipt: Verify accuracy using mass of water. Spectrophotometric method may be used for extremely low volumes.

Annually: If used, calibrated micropipetters should be calibrated annually and adjusted or replaced if the precision or accuracy is greater than 2.5%.

Refrigerator / Freezers

Refrigerators should maintain a termperature of 1°C to 5°C. Calibrated thermometers should be graduated in at least 1°C increments and the thermometer bulb immersed in liquid.

At Installation or after non-routine maintenance: Validate uniformity of temperature by mapping the refrigerator / freezer chamber

Daily: On days the refrigerator is in use and the laboratory is staffed record the calibration-corrected temperature, date, time, and technician's initials.

Sample Containers

Microbiological drinking water sample containers should be wide-mouth plastic or non-corrosive glass bottles with non-leaking ground glass stoppers or caps with non-toxic liners that should withstand repeated sterilization, or sterile plastic bags containing sodium thiosulfate. Other appropriate sample containers may be used. The capacity of sample containers should be at least 120 mL (4 oz.) to allow at least a 1-inch head space.

Glass stoppers must be covered with aluminum foil or char-resistance paper for sterilization.

Glass and plastic bottles used for microbiological analysis of drinking water that have not been presterilized should be sterilized by autoclaving. Glass bottles may also be sterilized by dry heat. Empty containers should be moistened with several drops of water before autoclaving to prevent an "air lock" sterilization failure.

If chlorinated water is to be analyzed for microbiological parameters, sufficient sodium thiosulfate must be added to the sample bottle before sterilization to neutralize any residueal chlorine in the water sample. Dechlorination is addressed in Standard Methods 9060A

Temperature Monitoring Device

Glass, dial, or electronic thermometers used for microbiological drinking water analysis must be graduated to 0.5°C increments (0.2°C increments for tests which are incubated at 44.5°C) or less except as specifically noted for refrigerators. The fluid column in thermometers should not be separated.

Daily: Each day of use a single check of any infrared thermometer in use should be made by checking the temperature of a bottle of water at the temperature of interest that contains a calibrated thermometer. Agreement between the two should be within 0.5°C or the device should be recalibrated.

Quarterly: Digital thermometers, thermocoupes, and other similar electronic temperature measuring devices should be calibrated at least quarterly. The date the thermometer was calibrated and the calibration factor should be kept and be available for inspection.

Semi-Annually: Infrared thermometers should be verified at least every six months using a NIST certified thermometer over the full temperature range that the IR thermometer will be used.

Annually: Liquid bearing thermometers such as mercury or alcohol thermometers need to be traceable to NIST calibration and verified at least annually and whenever the thermometer has been exposed to temperature extremes. The correction factor and date of calibration should be indicated on the thermometer and maintained as part of the equipment maintenance log. If a thermometer's correction factor is greater than 1°C then it should not be used for microbiological drinking water analysis. Thermometer verification records must include:

Serial number of laboratory thermometer
Serial number of NIST-traceable thermometer
Temperature of laboratory thermometer
Temperature of NIST-traceable thermometer
Correction factor
Date of check
Analyst's initials

Every 5 years: The NIST traceable thermometer should be recalibrated at least on per 5 years.

Ultraviolet Lamp

Monthly: The lamp should be disconnected monthly and cleaned.

Water Activity Meter

Daily when in use: Verify water activity of known solutions

Water used in all analyses

Monthly: Verify water meets reagent grade water specifications. Reagent grade water requirements are as follows:

ASTM type 1: Conductivity <0.056 µS/cm at 25°C, TOC <50ppb, Sodium <1ppb, Chloride <1ppb, Silica <3ppb
ASTM type 2: Conductivity <1.0 µS/cm at 25°C, TOC <50ppb, Sodium <5ppb, Chloride <5ppb, Silica <3ppb
ASTM type 3: Conductivity <0.25 µS/cm at 25°C, TOC <200ppb, Sodium <10ppb, Chloride <10ppb, Silica <500ppb
ASTM type 4: Conductivity <5.0 µS/cm at 25°C, TOC no limit, Sodium <50ppb, Chloride <50ppb, Silica no limit

Water used in microbiological analysis

Monthly: Verify acceptable levels of chlorine and aerobic plate count. Reagent grade water requirements are as follows:

ASTM type A: Maximum Heterotrophic Bacteria Count <10/1000mL
ASTM type B: Maximum Heterotrophic Bacteria Count <10/100mL
ASTM type C: Maximum Heterotrophic Bacteria Count <100/10mL

Weights

Semi-Annual: Non-reference weights used for daily balance checks should be validated at least every 6 months with NIST traceable reference weights. Correction values should be on file and used.

Every 5 years: Reference weights should be recertified at least every 5 years. Damaged or corroded weights should be replaced. Maintain NIST traceable documentation as a record