106.11 Metric Implementation
This article establishes standard procedures for inspection and reporting of materials on metric contracts or with metric paperwork. For contract work that refers to Sec 106.11, Metric Implementation, will handle most authority needed for enforcement.
The values stated in the Engineering Policy Guide in either English or metric units are to be regarded separately as the standard. Within the text, the metric units are shown in parenthesis. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other.
Above all, it is important that documentation correctly identify the material and its manufactured units. If needed, a conversion can be performed for payment quantities purposes.
In a precise ("soft") conversion, a measurement is mathematically converted to its exact (or nearly exact) equivalent. With an approximate ("hard") conversion, a new rounded, rationalized metric number is created that is convenient to work with and remember.
Megagram is the metric version of a ton, not "tonne" or long ton.
On the contract tab in SiteManager (SM), quantities should be entered to the official unit for that material code. For contracts generated after May ’04 the official unit is displayed on the contract tab. Contracts generated before then should be reported to the units designated on the sampling checklist for that material.
When a project is designed and specified in metric units, all SM reports to that contract are to be in metric with the exception of concrete.
If materials are “presented” in units other than the contract units, it is a good practice to place the “presented” units and quantity on the sample tab of a SM record. The official units and contract quantities can then be placed on the contract tab.
Reports to Maintenance, General Services and other MoDOT divisions for other than construction work should be in the units as bid, normally English.
Normally, when converting from English to metric, if one maintains the same number of significant digits, the same accuracy will be maintained, e.g. 125 ft. (3 digits) converts to 38.1 m (3 digits).
AASHTO R1-04 is considered the final metric authority. Refer to Table 106.11 for some common conversations. This may be critical in some instances, as it is not uncommon for calculators to be off from the official multiplier. In all cases, where some form of equipment does the conversion, the multiplier used should be checked. For the transportation industry, the following are considered as standards. Do not use multiples of 10 such as centi, deci, etc. except in rare instances where it eliminates a lot of decimal places. Example: In a range between cubic millimeters and cubic meters there is a lot of space and cubic centimeters may be appropriate, but should normally be avoided. Common units are gram and meters with prefixes of milli (10-3), kilo (103) and mega (106).