The Mechanical Insulation Design Guide (MIDG)

At our recent TIAC yearly conference in Edmonton, AB (Sept. 13-16, 2008) we were introduced to MIDG (the Mechanical Insulation Design Guide) by Michele Jones (the Executive Vice President) of the NIA (National Insulation Association), our American sister organization out of Alexandria, Virginia. She explained that The National Institute of Building Sciences (NIBS) through the National Mechanical Insulation Committee (NMIC) has developed the MIDG to provide a comprehensive source of information on the performance, use, testing and standardization of mechanical insulation in buildings and industrial facilities.

Without a doubt, this is the most thorough and exhaustive compilation and interactive resource ever put forward on the topic. I quote from the introduction "[The guide] is intended to be a comprehensive resource to assist specifiers and users of mechanical insulation in the design and specification of mechanical insulation systems for a wide range of applications." Further, "Insulation is applied but rarely engineered. With the best intentions, but not necessarily with thorough knowledge, many specifications have evolved over the years primarily based upon modification of old documents. This practice combined with the lack of mechanical insulation educational and awareness programs as to the value in having a properly engineered, installed and maintained mechanical insulation system has led to the underutilization of mechanical insulation in energy conservation, emission reduction, process and productivity improvement, life cycle cost reduction, personnel safety, life safety, work place improvements and hosts of other applications".

MIDG is a website www.wbdg.org/midg that walks the designer through an introduction and scope of the design guide and then draws design objectives and design considerations. Mechanical insulation encompasses all thermal, acoustical and personnel safety requirements in:

• Mechanical piping and equipment, hot and cold applications
• Heating, Venting and Air Conditioning (HVAC) applications
• Refrigeration and other low temperature piping and equipment applications.

There is a complete analysis of all the physical properties and performance criteria of all generic insulation types:

• Cellular
• Fibrous
• Granular
• Reflective

A link to the NIA provides further links to member manufacturers' websites. In this way, the various manufacturers represent each of these insulation types and, in turn, individual data pages and submittals are made available. This link to the manufacturers' websites ensures that the information is as current as possible.

In the design data section there is a collection of information and a product selection chart, searchable by temperature as well as some simple calculators that allow the calculation of heat flow and surface temperatures. This section contains information on:

• Estimating heat loss and heat gain;
• Controlling surface temperature;
• Determining dimensions of standard pipe and tubing insulation; and
• Estimating heat loss from bare pipe and tubing.

Online interactive MIDG calculators include the following:

• Calculator that estimates time to freezing fluid in an insulated pipe. This calculation estimates the time for a fluid-filled pipe (no flow) to reach a freezing temperature.
• Temperature drop calculator. This tool calculates temperature drop of a fluid flowing in a duct or pipe.
• Simple thickness calculator. This calculator estimates the thickness of insulation required to obtain a specified surface temperature.
• Simple heat-flow calculator. This calculator estimates heat flow through an insulation for flat and cylindrical systems.

There are further links to other resources including ASHRAE, ASTM and NFPA, to name a few.

"The MIDG provides users with a single platform for increasing their knowledge of mechanical insulation in an efficient, easy-to-understand, cost-effective manner."

As we all know in TIAC, there is no single component of a mechanical or HVAC system that is as energy efficient and cost-effective as properly installed insulation. Now there is one more tool (MIDG) to help in the understanding and proper design of insulation products into these systems.