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The NECA Manual of Labor Units and The Role of Construction Specifiers

Jan 3, 2022

The 2021-2022 edition of the NECA Manual of Labor Units (MLU) is the latest edition of NECA’s flagship publication. Since 1923, the MLU has been the estimating resource of choice for electrical contractors, providing an experience-based reference for estimating the electrical construction labor required to install typical electrical and communications systems.

The MLU has continuously evolved over its nearly 100-year life and in 2016, we reformatted the Manual to follow the Construction Specification Institute’s MasterFormat to better assist electrical contractors with their estimating processes. This article is to help you understand the reasoning behind that change and the role the construction specifier plays.

Learn more about the MLU at

Standards and the Role of Construction Specifiers

At the beginning of every project, the design team produces specifications and drawings that drive what is to be built. We don’t often hear about the role of specifiers and the standards they use, such as MasterFormat, but it is important to understand the relationship between designer, specifier, and the specifications they produce. To that end, in this article, Ron Geren, FCSI, CCS, CCA, CDT, CSC, SCIP and former chairman of the Construction Specifications Institute, shares his insight into the work of specifiers.

The following is adapted from an interview with Ron Geren on his experience as a specifier and the evolution of building lifecycle standards in the construction industry.

The key role of specifiers is to take the design information from architects and engineers and break down the design into specific building materials and products, ensuring that the materials and components fit the requirements of the design. The specifier can be involved throughout the entire duration of the project, though the bulk of their effort is during the design process.

While the drawings indicate the size and shape of the components, and where things go, the drawing does not contain detail about the materials needed. A specification defines the building materials based on performance or certain characteristics, in some cases limiting the building product to specific sources or manufacturers.  

Specifications will also deal with the installation of materials and components. This level of detail is simply too much information to put directly on drawings—it would overwhelm the graphic nature of the drawing. A specifier will create a separate specification document, based on a standard three-part structure:

PART 1 of the spec, “General,” includes administrative information: submittals, payment options, project conditions, and quality assurance items that can be defined up front.

PART 2 is “Products,” the meat of the specification. Building products will be described in their characteristics and basic performance requirements. This PART will address any shop fabrication that needs to be done, for components that are not manufactured. Included in this section are any finishes applicable to the product; but this part of the spec does not detail the physical installation of materials on the job site.

That is where PART 3, “Execution,” comes in. Once the products and materials are delivered to the job site, PART 3 describes how the product will be installed on the project. Details a specifier will focus on here include tolerances involved in the installation, ensuring that the final product is involved within a certain tolerance range. In addition, there may be field quality criteria noted such as inspections or testing.

To create these specifications, the work of a specifier involves gathering information from the design team, researching the types of materials that are being proposed, and assessing their potential characteristics—then sometimes advising the design team on product or material choices. With their research, the specifier develops the three-part specification that is published in a project manual. This manual contains the specifications and related construction documents; generally procurement and contracting documents, with bidding information, agreement, and general conditions. This information is then published along with the set of drawings. Together, these materials will be used by contractors to create their bids and proposals, and will also serve as the guiding documentation for administering and constructing the project.

The specifier is constantly looking at all the materials on the project: what their applications are, how they interface with other materials on the job site, and what materials are compatible with each other. Once the specifications are put together, the specifier might advise the design team during the procurement process, when contractors submit substitutions. The specifier will review substitutions to see if they meet the intent of the design and requirements of the specifications.


All of this brings us to MasterFormat, which is the industry standard for organizing specifications throughout a project. MasterFormat is a classification system that the Construction Specifications Institute (CSI) developed in the 1960s to organize construction information. Initially, it was intended just to organize the way specifications are published for construction.

Prior to the development of MasterFormat, architects and engineers wrote specifications using their own formats. A contractor going from one job to the next would not know where to find necessary information, because the information would be structured differently from one architect's office to the next.

MasterFormat was originally created with 16 divisions. This established a standard organizational structure; for example, Division 8 for doors and windows. With MasterFormat, everybody knew to look for information about doors or windows in Division 8 of the project manual. This simplified the process, making it easier to communicate necessary information between the design team, specifiers, and contractors.  

MasterFormat has grown over the decades, and now we have more than just divisions. Numbers and titles within those divisions provide additional detail for the growing complexity of building projects and data management, and those numbers have changed over time. First, there was a five-digit structure through 1995, and the MasterFormat 1995 structure can still be found in use to this day.

In 2004, CSI made a major change to MasterFormat. With the old 16 divisions system, there was not enough capacity for all the materials and technologies developing in the construction industry. CSI expanded MasterFormat to include 50 divisions, 49 of which specifically address construction specifications. The remaining division focuses on non-specifications, such as procurement and contracting requirements.

Within the 49 specification divisions, there are multiple numbers and titles that break down into specific work results. A work result is essentially a material or a product, plus the labor to install it. For example, carpeting is a Division 09 material in a MasterFormat. The type of carpeting specified would be dependent upon what the architect wants—whether carpet tiles or rolled broadloom (sheet) carpeting, that level of detail is captured in the Division 09 carpeting section.



UniFormat was created to provide a classification system for building elements, encompassing a broader scope than the individual work results and detail that MasterFormat addresses. Instead of specific materials, UniFormat is used to classify the overarching building system, including exterior walls, interior walls, roof systems and overall building envelope.

This separate organizational structure is useful in schematic design and early phases of the design project. At this stage, the architect isn't considering what kind of adhesives are going to be used to hold something together. They're thinking “what am I going to make this building out of?” The design team is considering what the building envelope is going to entail, what that roofing system is going to be, what kind of structural system is going to be holding the roofing system up, and what kind of foundation systems is going to be needed to support all the above. And on the inside, they are thinking what kind of wall construction is going to be necessary in order to divide the spaces. At this point in the process, the design is not getting into the various details associated with each one of those assemblies.

UniFormat is organized around these basic building elements, so you can describe the building at an earlier stage focusing on major building assemblies, rather than getting down into the weeds of what each individual material is associated with that assembly. Within a given project, design teams may begin the project in UniFormat and need to transition to MasterFormat to detail building products and work results.


Modern workflows are data driven, and industry standards such as MasterFormat and UniFormat are increasingly used to organize project data beyond specifications and building products. Crosswalk is an essential tool for filtering the massive amount of construction information available, both within project archives and in the marketplace, and enables teams to access vital information as quickly as possible.

If a project starts out in UniFormat and now needs to transition to MasterFormat, data can be easily translated to MasterFormat by using Crosswalk. Beyond construction specifications, project data—including cost codes, bids, estimates, change orders, and work orders—can also be organized using OmniClass tables, numbers, and titles.

Crosswalk is indispensable for teams seeking to “standardize” or update project data to a common organizational structure. Many general contractors, for example, have decades worth of specifications and project data organized with MasterFormat 95. With the change in structure from 16 divisions to 50, manually updating or referencing past project data can be time-consuming and error prone. With Crosswalk, you can easily re-classify data from MasterFormat 95 to modern MasterFormat, eliminating costly manual entry and digitally connecting archived data.

Learn more about the Construction Specifications Institute at