MasterFormat 2004 Numbering

In order to address new topics and expand the structure, the number of divisions has been reorganized into Groups, Subgroups and Divisions, and the number of divisions increased from 16 to 50. A new subgroup named Facility Construction (Division 02-19) under the Specifications Group covers general construction subjects that are similar to those in the 1995 edition. Other subgroups under the Specifications Group are General Requirements, Facilities Services, which has new separate divisions for plumbing, fire suppression, electrical, communications, integrated building systems, electronic safety and security systems, and heating, ventilation and air conditioning (HVAC), Site and Infrastructure (transportation, utility and marine construction), and Process Equipment (industrial and process engineering subjects).

To enable MasterFormat users to handle the volume and complexity of today's projects more expeditiously, the numbering scheme has been revised to allow it to more adequately cover the subjects of MasterFormat and to provide room for future addition of new subjects without restructuring the entire system. The previous five-digit numbers have been expanded to allow room for more subjects at each level of classification and thereby accommodate more consistent classification. The five-digit numbers had limitations because of the way each of the five digits were employed. The first two digits represented the Division, with the remaining three digits left to set a hierarchy of subjects within each Division. Because only a single digit was assigned for each Level after the Division, the number of possible Level 2 subdivisions within each Division was held to nine. Similarly, the number of categories available at Level 3 and Level 4, which was unassigned by MasterFormat, were also limited to nine each. In many Divisions, this small number of available spaces for information was too limiting, and MasterFormat simply ran out of room to properly address topics. This lack of room often resulted in inconsistent classification, such as the insertion of topics such as Cathodic Protection, Lightning Protection, Fire Suppression, Detection and Alarm, and Solar and Wind Energy Equipment into Division 13, rather than other Divisions such as 15 or 16 where they would fit more appropriately, simply because there was available room in Division 13 and there wasn't in the others.

The solution to these limitations was to add a sixth digit, and the six digits were arranged into three sets of paired numbers. These pairs of numbers allow for many more subdivisions at each level and the main six-digit number still represents three levels of subordination, as the published numbers in previous editions of MasterFormat have done. Another advantage of grouped pairs of numbers is that they, like telephone numbers, are easier to recall.