Metrology Laboratory

It is the Colorado Metrology Laboratory's policy to provide timely measurement services of the highest quality attainable meeting statutory and regulatory requirements to field staff and customers, through continuous improvement of the management system.

The Laboratory is equipped with the latest technology for standards calibration and is traceable to theNational Institute of Standards and Technology(NIST) through acertificate of traceability.

The laboratory provides calibration services in:

  • Mass (Echelon II & III)
  • Volume (100 gal - 5 gal)
  • Time/Frequency (tuning forksand LASER speed units)
  • Grain Moisture (< or= 25%)

Schedule a Calibration Service

Before sending any work to the Colorado Metrology Laboratory, you must first call to make your initial request for calibration. All work will be scheduled as soon as possible after the initial request, depending on the current lab workload. If there are questions about your request, one of our metrologists will contact you for clarification.

After the lab has determined the amount of time it will need to process your request, you will be contacted and provided a calibration date. If you need to ship any items to the lab, please make sure they arrive prior to your scheduled calibration date.

If there are any specific requirements, such as:

  • Artifacts are sent to lab by one company, but the certificate is to be issued to another company
  • Certificate is to be sent to one address, but the invoice sent to another address

These instructions need to be included with the artifacts when they arrive at the lab.

For large mass (50 lb - 5,000 lb & weight carts)

  • Deliveries and pickups are limited to Fridays only, unless pre-approved by a lab metrologist.
  • Standards must be delivered on an open-bed truck or a truck with a lift-gate. An overhead hoist is available.
  • Truck maximum length is 45 feet (including the cab) due to limited street access.

Any deviation from the above guidelines will result in the shipment being refused and sent back to the customer.

Services and Fees

The Colorado Metrology Laboratory offers a wide range of calibration and testing services. These services are available to both the public and private sectors on a fee basis. Calibration services are offered in the areas of mass (weight), volume, length, grain moisture, and time/frequency in both customary and metric units. The laboratory is capable of performing calibrations at varying levels of accuracy.

Many standards do not need calibration at the highest levels and in fact, may not be stable enough to maintain high accuracy. We will gladly answer your questions regarding what kind of calibration will best suit your needs by contacting us. We can also assist in specifying standards that you are looking to purchase. Please see FAQs to help answer some general questions.


Laboratory fees are $40 per hour. There is a minimum charge of one hour for all orders. Please contact us for a quote for your specific item(s).

Calibration Services


Description/ Weight Classes



Mass Echelon II

ASTM 2,3; OIML  F1

Precision Weight Set for Precision Balances/ Comparators

10 kg - 1 mg

Mass Echelon III

ASTM 4,5,6,7

NIST Class F

OIML M1, M2, M3

Stainless Steel weights, Weight Sets, Dead Weight Testers Cast Iron Weights

25 kg - 1 mg

2,500 lb - .001 lb

4 oz - 1/32 oz

Volume Transfer

Provers, Test Measures

5 gallon test measures
100 gallon provers

100 gal - 5 gal

Time/ Frequency


Tuning forks, LASER speed units

<= 100 mph

Grain Moisture


Corn, Millet, Pinto Beans, Sunflower, Barley, Sorghum, Wheat

<= 25 %

Cleaning Standards

Standards Conditions/Cleaning

All standards that are delivered to this laboratory must be submitted clean and, where required, painted. Cleaning and/or repair of standards in the metrology lab can be considerable and added to the calibration costs.

Precision Mass Standards

  • Precision Weights have very tight tolerances, thus requiring gentle handling and proper storage before, during, and after calibration.
  • Unless your management system prohibits, pre-clean each weight with a cotton swab and/or dust-less 'kim' wipe lightly dampened with ethanol. Let Air dry before placing back into their case.
  • Remove dust and other foreign objects from the cases.
  • All cases must be properly marked with an identification number. If this is missing, the laboratory will issue a generic identification.
  • When shipping individual weights, please pack each weight with tissue paper, NOT BUBBLE WRAP. Plastic-based packing materials will leave residues on weights.
  • For weights that are shipped inside of a case, please wrap the case with tape or rubber bands to prevent the case from opening and spilling the tiny weights in the box during shipping.

Non-Precision Mass Standards

  • Weights should be clean and in good repair. Except for weights that have been submitted to the laboratory in the past and have shown that they can maintain tolerance, all weights submitted must meet the requirements of NIST HB 105-1.
  • An ethanol-dampened rag cleans stainless steel weights well.
  • Interior cases for weight kits should be wiped down or vacuumed.
  • Cases should be sound with secure latches.
  • Cast Iron weights should have no evidence of rust, loose paint or adhering debris.
  • Do not "power wash" cast iron weights as this creates divots in the material, removes too much paint, and introduces water into the adjustment cavity. This can be considerable to the overall cost.
  • Light sanding with steel wool and wipe down with mineral spirits works well to clean cast iron.
  • Cast Iron weights should be painted with a light coat of aerosol paint.
    • Silver/Aluminum color for customary weights
    • Gold color for metric weights
  • Do not use epoxy or enamel paint.
  • During colder months, large cast iron weights should be kept indoors the night before calibration to keep them as close to room temperature as possible when arriving. We cannot calibrate weights that are wet.
  • Companies bringing in large weights should only drop off/pick up on Friday. Any other days, they will be refused unless pre-approved by a metrologist.
  • Weights should be identified with a permanent stamp or mark into the surface of the weight. Stickers are not allowed and will be removed.
  • If no permanent markings are present, the lab will issue a generic identification.
  • Handle your analytical weights carefully. Tolerances are small, so dirt or abuse can throw them out of tolerance. Adjustments add cost to your calibration.

Weight Carts

  • Make sure the cart is cleaned to remove debris, oil, and rust. Do not forget the tires.
  • Fill the gas tank to the specified reference line. This is usually an etched line into the gas sight tube.
  • Make all repairs/tune ups/replacements just prior to submitting the cart into the lab. Making changes to the cart in any way voids the current certificate and must be submitted back into the lab for recalibration.
  • Ensure all pieces of the weight cart are included when delivering the weight cart. For example, electric carts sometimes have an extension rod for the power cord. This is included in the overall calibration of the cart. Missing pieces extend the amount of time you are without your standard until we receive all parts.
  • If you make any major repairs/adjustments/replacements to the cart prior to submittal, let the metrologist know for record keeping purposes upon submittal. For example, if you add an extra spreader bar to the body of the cart, this is viewed as a major adjustment. Another example is if you have to replace the engine, gas tank, or hydraulic tank, this is viewed as a major repair/replacement. This not only helps us for record keeping, but it also saves time on calibration if we know if there was a significant change to the overall mass.

Dead Weight Testers

  • Weights should be clean of dirt, debris, and oil before sent to the lab for calibration.
  • All pistons should be complete with sleeves (if applicable). If the piston is incomplete or missing the sleeve, the piston will not be calibrated and will slow down the turnaround time until all parts are supplied.
  • All weights and pistons should be marked with a serial number or other identifying markings.
  • If no markings are present, the lab will issue a generic identification.

Volume Standards

  • Large volume provers and five gallon test measures must come in clean and painted if made of mild steel with no strong odors or evidence of hydrocarbons.
  • Any vessels with obvious residues will be refused and returned to the customer.
  • Be sure the prover has working valves, a clean glass gauge tube, and a readable gauge plate. Markings made by a permanent marker or anything other than the original etchings on the plate will not be accepted.
  • Be sure the mechanism for adjusting the prover can be moved freely.
  • Provers and test measures will not be tested if they come in with leaks, dents, or badly corroded interiors.
  • If any of the above conditions are found, the item will not be tested and will be returned to the customer for repair; please refer to NIST HB 105-3.

Time/Frequency Standards

  • Tuning forks should not be paired together with adhesive tape. Rubber bands, envelopes, and bags are excellent alternatives.
  • Tuning forks should be permanently marked with: frequency band, miles per hour rating and serial number.
  • LASER units should be supplied with batteries or car adapters that are fully charged.
  • Shipments of tuning forks and/or LASER units should be packed securely and include contact information.
  • Walk-ins are limited only to WEDNESDAY. Any other days must be pre-approved by a metrologist either using the request form or calling directly.
  • If a delivery is made other than Wednesday, we cannot guarantee that the equipment will be tested the same day.
Shipping Items

All items should be securely packed before shipping. Any item ten pounds (10 lbs) or more should be shipped in wooden crates and/or palletized. The Metrology Lab is not responsible for items improperly shipped.

Items should be individually wrapped or protected with appropriate packing materials.

If you are shipping small weight kits, be sure to secure them in the closed position with latches, rubber bands, tape, boxes, or bags. Small weights can be lost if the kit is not securely closed, delaying your calibration test.

Fifty pound (50 lb) weights or larger whether shipped or delivered, should be on an open-bed truck or with a lift-gate. An overhead hoist is available for delivery.

Any deliveries arrivings on trucks without a lift gate or an open bed will be refused and sent back to the customer.

Delivery truck length is limited to 45 feet (including cab) due to the location of the lab in a residential area with narrow streets.

Return shipping arrangements should be made with the metrology lab at the time of the initial phone call and scheduling. Utilizing the owner's freight account or shipping the weights back "freight collect" are preferred and recommended methods.

Return shipment of small boxes (150 lbs or less) will usually be shipped via best shipping method. If a customer has no preferred shipper, current shipping charges will be added to the invoice along with the calibration charges.

The laboratory will not accept items shipped by truck that are "freight collect."


Laws and Regulations

Colorado Revised Statutes

Colorado Revised Statutes are made available for public use by the Committee on Legal Services of the Colorado General Assembly through a contractual arrangement with the LexisNexis Group. Any person wishing to reprint and distribute all or a substantial part of the statutes in either printed or electronic format must obtain prior permission of the Committee on Legal Services; permission is not required to reprint fewer than 200 sections of C.R.S. (please see §2-5-118, C.R.S.).

The Lexis Nexis website is the only official source of the Colorado Revised Statutes.

Instructions for using Lexis Nexis

Title 35, Article 14: Measurement Standards ACT, Sections 35-14-101 to 35-14-134

Related Links

NIST Certificate of Traceability

  • Certificate on NIST site.

National Institute of Standards & Technology (NIST)

  • Technology Services provides a variety of products and services to U.S. industry and the public in collaboration with NIST laboratories, federal agencies, national measurement institutes, state and local governments, and the private sector.

Metrology Contact List

  • State Laboratory contact information

National Conference of Standards Labs International (NCSLI)

NIST Handbook 143

NIST Handbook 150

National Voluntary Lab Accreditation Program (NVLAP)

  • NVLAP is part of the Standards Services Division within NIST's Technology Services.

NIST Handbook 105 Series

Handbook 105-1

  • Class F Weights & Mass Standards

Handbook 105-2

  • Glass Flasks

Handbook 105-3

  • Graduated Neck Volumetric Test Measures and Provers

Handbook 105-4

  • Liquified Petroleum Gas Type Provers

Handbook 105-5

  • Stopwatches

Handbook 105-6

  • Thermometers

Handbook 105-7

  • Dynamic Small Provers

Handbook 105-8

  • Weight Carts


Q:   Why clean my weights?

A:   Cleaning your weights should be a standard practice before submitting your weights for calibration. Proper cleaning removes debris, rust, corrosion and any other extraneous material from the weight that could cause the weight to measure out of tolerance. Proper cleaning also extends the life of the weight, especially cast iron standards, as they are more susceptible to rust and corrosion. If rust and corrosion are removed on a regular basis, it slows the breakdown of the material. On a cost basis, cleaning your standards prior to calibration reduces the amount of time required, and thus lessens the charge. If your weights come into the metrology lab dirty, rusty, or full of water, we reserve the right to reject the item. If the weight is not repairable, we also reserve the right to condemn the weight from further use.

For proper cleaning recommendations of your standards, refer to Standard Conditions/Cleaning.

Q:   What is the recommended procedure for cleaning weights?

A:   Please refer to Standard Conditions/Cleaning. If you have additional questions, please contact us.

Q:   Can you answer questions regarding the price of petroleum/gasoline?

A:   For questions concerning the price of gas, over/under charging at the gas pump, gas quality, complaints, etc. please refer to the Oil and Public Safety, a Division of the Colorado Department of Labor and Employment, at (303) 318-8525.

Q:   How long is my turnaround time?

A:   Upon request for calibration of your standards, a metrologist will give you an estimate of what the turnaround time will be for your standards. If the original turnaround time quoted changes, we will contact you as soon as possible. The average turnaround is 5 to 10 business days with the following possible exceptions:

  • Precision Standards take longer for calibration due to longer equilibration times in the lab
  • Submitting a large number of weights at one time can take longer in order to complete the request
  • If the standards are out of tolerance and need to be adjusted
  • Missing equipment pieces. This applies, but is not limited to, weight carts and dead weight testers
Q:   What is measurement uncertainty?

A:   Measurement uncertainty is a parameter, associated with the result of a measurement, that defines the range of the values that could reasonably be attributed to the measured quantity. When uncertainty is evaluated and reported in a specified way, it indicates the level of confidence that the value actually lies within the range defined by the uncertainty interval.

Q:   What is measurement traceability?

A:   Traceability is the property of the result of the measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty.

This chain of comparisons, calibrations, tests, and other terms that imply a measurement involves increasing levels of accuracy for each measurement in the hierarchy reaching or traceable to the highest accuracy level or measurement origin. This measurement origin is normally standards and procedures maintained at the National Institute of Standards and Technology (NIST).

Q:   Why do I have/do not have an expiration date on my certificate?

A:   If you are a scale or service company:

  • You are required to have an adequate amount of weight to properly test/repair/place in service scales for your customers. These standards are required to be calibrated by an accredited metrology lab on an annual basis. We issue a certificate with a one-year expiration date. These standards MUST be submitted on or before the one year expiration date.
  • We accept other accredited metrology labs to complete this work for you. For a list of accredited labs, please refer to the Metrology Lab Contact webpage. To be considered "accredited" the lab MUST be at least have a CURRENT NIST certificate of traceability certificate. Please see our certificate of traceability as an example.
Q:   What are the requirements of a law enforcement agency?

A:   You are required to submit your standards (tuning forks and LIDAR) on an annual basis according to CRS 35-14-107(g). There is a one year expiration date included on your certificate. You must submit your standards on or before this date.

A reminder postcard will be sent to the current contact name we have on our database. These are usually sent out approximately one month prior to the expiration date.

If the current contact name or address is incorrect, please fill out a new postcard request form and we will update our database.

Q:   What are the requirements of a commercial or private company?


  • We do not issue an expiration date unless you specify one to our lab to comply with your current management system requirements.
  • If you did not request a specific expiration date, we issue a generic statement Certificate expiration to be determined by owner using the procedures in the National Conference of Standards Laboratories International (NCSLI) Recommended Practice RP-1, Establishment and Adjustment of Calibration Intervals. To purchase this manual for your review, please visit the NCSLI website.
  • If you like to have a specific expiration date added to your certificate, please contact us.
Q:   What is a reminder postcard?

A:   To better serve our legal customers (scale companies and law enforcement agencies), we automatically provide a free "reminder postcard" service. We send out this reminder approximately 1 month prior to when the standards are due for calibration (2 months for large mass).

We also provide this service to our private and commercial companies who require their standards to be done on a timed basis according to their management system requirements on a request only basis. This is a gentle reminder to you to bring in your standards prior to the expiration. To request this service for your standards, please contact the Metrology Lab and ask for a postcard request form.

Q:   Why have I never received my reminder postcard?

A:   There are several reasons as to why you never received a reminder postcard:

Private or commercial companies:

  • You are not required to have an expiration date stated on your certificate. If you wish to have an expiration date issued on all of your future certificates, contact us. Please refer to your own management system requirements for calibration intervals for your standards.
  • To request a postcard reminder, please contact us and ask for our postcard request form.

We do not have current contact information in our database.

  • If you have recently changed addresses, P O Boxes, or an employment change, please contact us. If our database is different, we will correct it immediately.

The postcard was sent to the wrong person

  • The person submitting the equipment may not be appropriate to receive reminder postcards.
  • The person may no longer be employed with your organization
  • You may have a designated person who is in charge of calibration intervals and we do not have it listed on our database.
  • If you need to designate an appropriate person to receive these postcards, please contact us
Q:   How should I ship and/or pack my equipment?

A:   The lab strongly encourages packing your standards properly to limit damage during transport to our facility. The lab is not responsible for items not shipped properly. If a package arrives in poor packaging, we try to repack it properly to limit the amount of damage leaving our facility. You may be charged accordingly if extensive repacking is required. Please refer to Shipping Items for specific information.

Q:   How should I deliver my large mass?


  • We require all large mass (50 lb and larger) to be delivered on Fridays only unless pre-approved by a metrologist.
  • All deliveries must be on an open-bed truck or a truck with a lift gate. We have an overhead hoist available.
  • Truck length is limited to 45 feet (including cab) due to residential street restrictions.
  • For more information, refer to Shipping Items.
  • Any deviation from the above requirements, the delivery will be refused and sent back to the customer
Q:   Why can't my weights be calibrated the same day they are delivered?

A:   There are several reasons why we cannot calibrate weights on a same day basis.

  • All weights must acclimate to our laboratory environmental conditions before calibrating.
    • Precision weights must be placed next to the balances and working standards prior to calibration at least 1 week for complete stabilization and accurate calibrations.
    • Large mass MUST sit at least overnight to limit the amount of sweating and allow the weight to stabilize to the laboratory's environmental conditions. This is especially true during the winter months. See "sweating" on weights below
  • Due to the active work load and customers who are already on the schedule for calibrations, we must take care of those appointments first.
  • We do not perform "rush calibrations" for any of our customers. We base our daily work load on appointments made on a first come, first serve policy.
  • The only exceptions to the "no same day calibrations" are law enforcement walk-ins on Wednesdays. Any other day of the week, we cannot guarantee same day turnaround.
Q:   What is sweating on weights?

A:   Weights that are brought into the laboratory form a thin layer of condensation on the surface. In other words, they "sweat". This is especially true during the colder months (cold outside into a warm and humid laboratory.) This layer of water adds enough weight to the standard that can throw the weight out of tolerance, thus forcing adjustment that can be avoided if the weights were allowed to equilibrate.

To resolve this problem, we only accept large mass on Fridays to allow the weight sit over the weekend to allow the condensation to evaporate and stabilize to the laboratory's environmental conditions.

Contact Us

Physical Address
Colorado Department of Agriculture
300 S. Technology Ct. Broomfield CO 80021

Phone number: (303) 869-9240
Fax number: (303) 869-9223

Tiffany Brigner
Deputy Division Director
Phone number: (303) 869-9230

Kate Smetana
Phone number: (303) 869-9241