There are a few popular topics that are a little more complicated than the typical fan selection. We often receive requests for "Explosion Proof Fans" and while this might not exist, we want to assist in any way we can. These resources will hopefully help answer some of your questions. All links will open in a new window, so please check your pop-up blocker if any of the links aren't functioning.
Motor Enclosures & "Explosive" Environments
There are three main categories of motor enclosures. We are often asked for an explosion proof fan, but the explosion proof actually relates to the motor enclosure, not the fan itself. Fans can be produced to meet certain spark resistant criteria, which will be outlined below. The three main categories are open drip proof (ODP), totally enclosed (TE--), and explosion resistant (EXP). Inside of totally enclosed their are common sub-categories: totally enclosed fan cooled, and totally enclosed air over are the most common. Contrary to popular belief, EXP is only a resistance, its not explosion proof. It actually only means the enclosure will withstand an internal explosion and not allow the internal flame or explosion to escape. See FA/113-01 below for more information.
The links below will open in a new window. Greenheck Application Guide: Motor Application Guide for Ventilation Products (FA 113-01)
This article also walks through all of the different explosive classes and divisions. Greenheck Application Guide: Explosion Resistant Disconnect Switches for Ventilation Products (FA 107-00) Greenheck Application Guide: Disconnect Switches for Ventilation Products (FA 106-00) 7 Most Common Motor Enclosure Types Defined by NEMA Standards
This article by the Electrical Engineering Portal has great motor visuals and brief explanations. NEMA Enclosure Types - NEMA.Org
A PDF by NEMA that outlines the differences between each electrical enclosure rating.
Spark Resistant Fans
There are three spark resistance categories. Spark A is the most strict, Spark C is the least strict, and Spark B is in the middle. Not all fans are spark resistant or carry an AMCA spark resistance listing, so there are technically four categories if you want to look at no spark resistance as the fourth. Greenheck has a great application guide that walks through the construction requirements of each category. It is important to know what Class and Division the environment is, the motor application guide is a great resource for that as well. Greenheck Application Guide: Spark Resistant Construction (SRC) (FA 116-08R) Greenheck Application Guide: Motor Application Guide for Ventilation Products (FA 113-01)
This article also walks through all of the different explosive classes and divisions.
Fan Efficiency Grades (FEG) - 2015 WSEC
Fan efficiency is becoming more and more important as energy codes become more and more strict. The new 2015 Washington State Energy Code mandates certain fans have a Fan Efficiency Grade (FEG) of 67 or greater and operate within 15% of their peak total efficiency. But what does that mean exactly, what fans are compliant, and how can you select a fan that meets this? Greenheck wrote an article that breaks this down back in 2013. The article is old, but still relevant. Greenheck also produced an energy guide that breaks down some models that have FEGs. However, this energy guide is out of date and there are some models that are obsolete and have been replaced with newer models. Greenheck Article: Understanding Fan Efficiency Grades (FEG) (CS 104-13) Greenheck: Energy Guide - Fan Efficiency Grades Catalog (July 2013)