What is KMD: meaning and how it differs from KM

What the letters stand for

KMD stands for «konstruktsii metalevi detalyuvalni», roughly «steel structures, detailing». The word that matters is the last one: on these drawings the structure is broken into parts, and each part can be made on its own.

In practice KMD is not a single sheet but a set, from general data down to drawings of individual parts.

KM and KMD: where the line runs

KM («konstruktsii metalevi», steel structures) is the stage where the engineer decides what the structure is made of and how it goes together: layouts, calculations, member sections. KMD goes further and describes how to make it in the workshop: every part with its dimensions, steel grade and connection details.

Put simply, KM lets you judge the concept and check the calculation, while KMD lets you cut, bend and weld the metal.

The contents of the sets and the design stages are covered in separate articles, linked below.

What a KMD set contains

The main set has four parts:

• general data;
• summary schedules and specifications, including the drawing list and the steel take-off;
• erection layouts with connection details;
• drawings of shipping elements and of individual parts.

A shipping element, or mark, is a piece of the structure that is convenient to transport: it leaves the plant as complete as possible, so less work is left on site.

The exact content depends on the type of structure. The full list and the way to read each sheet are in the article on KMD drawings and the article on KM and KMD stages.

When KMD is needed and who works with it

A steel structure is not normally fabricated without KMD: the KM layouts do not show every part and connection in the form a workshop needs. If the project has only reached KM, the next step is detailing.

The drawings reach several specialists, and each needs something different:

• the process engineer prepares material consumption rates, cutting layouts and programs for CNC machines;
• the production side makes the parts and assembles the shipping elements;
• the erector places the elements on site from the layouts.

For the client, KMD also shows the mass of the structure in the steel take-off. Deviations from KM are ruled out in detailing, and where they cannot be avoided they are agreed with the author of KM.

What to send to order KMD

The best starting point is a complete KM set with an overall steel specification. Without it the scope of work cannot be defined, and if a sheet is missing the estimate will be imprecise.

If there is no KM yet, begin with a technical specification and a description of the facility. Loads, climatic conditions and the material and coating requirements are needed too; with that set the work can start from the KM stage.

Price and lead time are individual: they depend on complexity, mass and how complete the source data is, so they are set after the documents are reviewed.

The drawings can be prepared together with steel structure fabrication: the POLYGONAL company designs with its own production technology in mind, so the drawings are easy to fabricate. The general service page is KM and KMD drawing development.

Where to read next

Further reading:

• KM-stage drawings: contents of the set and the stages of work;
• Drafting rules for KM and KMD drawings: the standard, the specification, scales;
• Structural calculation methods: what is checked before detailing.