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Nailor News is your source for content on relevant topics concerning Nailor Industries, Inc. and the HVAC industry. New product releases, case studies, product & project spotlights, employee interviews, trade publication articles, and general announcements are some of the content types you can expect to find in the Nailor Airwaves.

VAV Control: Terminal Unit Sequence Affects the Entire HVAC System

June 4, 2021
By: Matthew A Crump, PE

Developing real estate requires millions of decisions about what the building will look like, how to fit it within a budget, how will it operate, what HVAC system to use, etc., etc., etc. Each decision has an impact on the final product. One of these small decisions may never be consciously by the engineer designing the mechanical systems. As a junior engineer straight out of college, I was designing mechanical systems as a consulting engineer. This involved listening to the client, performing load calculations, and choosing the equipment to keep the...

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HVAC Ins & Outs with Dan Int-Hout - What is wrong with ADPI?

May 24, 2021
By Dan Int-Hout

The Air Diffusion Performance Index (ADPI) was developed at Kansas State University in the 1960’s as an ASHRAE project to assist in understanding air diffuser layout and performance. The basic concept is that the ratio of the discharge air projection, defined by the diffuser’s throw, and the separation distance between air outlets, could be used to define the resulting air mixing in a space.  The percentage of points in the “occupied zone” in a space that meet a criterion for acceptable “draft temperature” determined the ADPI. An ADPI of 80% was determined...

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VAV Systems: Ground Control to Major Tom

May 13, 2021
By: Matthew Crump, PE

Choosing the right equipment for your VAV system is critical, but it is only part of creating the right solution. The specified control sequences for each terminal unit will ultimately have the largest impact on eliminating any SPACE ODDITIES. ASHRAE has issued standard control sequences for terminal units in Guideline 36: High-Performance Sequences of Operation for HVAC Systems. The goal of the guideline is to provide uniform sequences the industry can use to optimize HVAC system performance. The selection of control sequence for each...

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HVAC Ins & Outs with Dan Int-Hout - Measuring Air Speeds

April 28, 2021

By Dan Int-Hout

The 1962 Air Diffusion Council Test Code 1062 required that room airspeed measurements be taken with an Anemotherm Air Meter. This was a battery-powered analog highly shielded hot wire anemometer, made by Reeves Hoffman, a sister company to Anemostat, located in Scranton Pa. It was the required instrument in the ADC 1062 test code, which was ”the bible” for air outlet measurements.  It was also the most popular and most readily available instrument for many years. It was, however, not without issues.


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VAV System Design: What is your style?

April 26, 2021

By: Matthew Crump, PE

The Houston, Seattle, and Washington DC markets largely specify systems that utilize series fan-powered terminal units in all zones. Dallas and Portland, OR, specify parallel fan-powered units on the exterior with single duct units in the interior. The equipment and configuration of selected terminal units appear to be a matter of style. There are many reasons why different areas could have different design standards. Regardless, analyzing why you would select one style over the other could provide some value...

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