Appropriate and calibrated tools are required at each location in order to comply with the Quality Assurance Program (QAP). As a minimum, this includes at least one four-corner scale and torque wrenches. It may also include a greater amount of tools, depending on the work performed at each location.
Types of Tools
NHTSA requires that load carrying capacity measurements are made using a scale that has an accuracy of one percent (1%) of the scale reading and that the calibration is traceable to NIST (US Sales) or Measurements Canada (Canada sales).
The calibration interval of the scale set shall be no greater than one year. Scale pads are comprised of sensitive electro-mechanical devices and recalibration of the scale should be performed if there has been any adverse handling of the scale set (ex. dropped or damaged).
Four-corner scales can be purchased from any scale vendor or manufacturer, but must meet the minimum requirement for weight capacity. NMEDA recommends that each wheel pad have a capacity of 2,500 Ibs. or more (10,000 lbs. total capacity), but at minimum must have the capacity to accurately weigh all vehicles that the dealer sells and/or modifies.
Torque wrenches are used to comply with mobility equipment manufacturer’s installation instructions. A dealer is required to have capable tools for every piece of equipment installed. In many cases that means that a dealer will need multiple torque wrenches as each torque wrench has a specific torque range and size. For example, if a manufacturer’s installation instructions require one piece of hardware to be tightened to 15 inch-pounds, and another at 70 foot-pounds, it is likely the dealer will need two separate calibrated tools because one tool alone may not have a range capable of accommodating each torque value. The calibration interval shall be as recommended by the tool manufacturer and calibration traceable to NIST (or Measurements Canada).
Tools such as volt-ohm meters, ammeters, capacitance-meters, or the combination type multi-meters, as well as pressure gauges and the like are required to be calibrated only when precise (quantitative) measurements are called out by the mobility equipment manufacturer.
For example, if a dealer is installing a piece if high-tech equipment that asks the installer to measure 3.4 Vdc +/- 0.2 Vdc, or something like 200 mA +/- 3.0 mA as part of the instruction, a calibrated tool is required. On the other hand, if a dealer is using a meter to troubleshoot or to check continuity or nominal automotive voltages there is no requirement to have a calibrated meter.
A best practice is to have all measurement tools calibrated.
Calibration of Tools
Personal vs. Company Owned Tools
NMEDA does not discriminate whose tools are used. The requirement is that the tool used is appropriate for the job and calibrated when applicable. Example, if each technician uses his/her own torque wrenches, then every technician’s torque wrenches should be calibrated.
Co-mingling of calibrated and un-calibrated tools
NOT RECOMMENDED. The best practice is all measurement tools in the shop, company owned or personal are calibrated.
If a dealer has multiple work area’s that employ multiple technicians and some tools are calibrated and some are not calibrated, then the dealer must provide objective evidence to NMEDA that only calibrated tools are being used as required. This means that the dealer must have a documented process in place and part of their Quality Control Manual (approved by NMEDA) that shows how tool management is accomplished. Failure to employ this type of process without written approval from NMEDA is a violation of QAP.
Evidence of Calibration
A physical or electronic calibration certificate is the most widely used form of evidence. This certificate is provided from the equipment manufacturer at point of initial sale, or by the calibration service provider. Note that most tools do not come calibrated, so always ask when purchasing equipment if there is evidence of calibration. Many retail stores provide calibration, but only when requested. The calibration certificate must show traceability to one of the industry standards NIST or Measurements Canada. Some calibration service providers offer web-based or electronic certificates and these are all acceptable forms of evidence. The dealer must also be able to show traceability from the certificate to the tool, that can be accomplished by using the tool’s serial number or a permanently affixed identification such as a label, scribe, or etched unique identifier (ID). If a tool does not have a serial number, the dealer is responsible to provide the needed identification.
Where to Buy and/or Calibrate Scales or Tools
NMEDA does not endorse or otherwise promote any particular tool manufacturer or calibration service provider, however, the companies listed have contract pricing and/or provide discounts to NMEDA members. Make sure to identify yourself as a NMEDA member when ordering and always ask for a calibration certificate to be provided that shows traceability to NIST (or Measurements Canada).
Longacre Racing Products
Let them know you are a NMEDA member for the special pricing.
(Caution: Some scales may not be capable for all vehicles due to maximum pad capacity.)
Calibration Service Providers
Scales (calibration provided on-site):
Tell them you are a NMEDA member. There is a contract rate that depends on your proximity in miles from the service center.
The Scale People Inc.
Tell them you are a NMEDA member.
Torque Wrenches, Meters, and Gages (calibration provided via mail):
Integrated Service Solutions (ISS)
Tell them you are a NMEDA member. Cost should be $25 per tool** when you provide your shipping number
Tell them you are a NMEDA member. Cost should be $22 per tool** when you provide your shipping number
**Applies to torque wrenches only. Other tools must be separately quoted.