LED light fixtures are becoming the industry standard and will likely replace fluorescent lighting.

With the energy efficiency and relatively small size of LEDs, lighting manufacturers have a tremendous amount of flexibility to create different shapes and sizes of light fixtures.  But with all of the advantages of LED light fixtures, there are always some disadvantages.

For instance, heat seems to be the kryptonite for LEDs.  The manufacturers have different methods of dissipating the heat generated by the LEDs….from odd looking heat sinks to heat rejecting fans.  For example..

Music Rehearsal Hall Lighting

During a recent project, I specified a pendant mounted cylinder with a LED light source to replace a similar fixture with an incandescent light source. The room was sizable with high ceilings and sound proofing for use as a music rehearsal hall.  I felt a LED fixture would be ideal for this application- energy efficient, easily dimmable, and no noisy ballasts as associated with a HID light source.

LED Light Fixtures

Noisy LED Light Fixtures

Music Rehearsal Hall after LED Light Installation

The project was nearing completion and everything was going smoothly until the light fixtures were energized. There was a low humming sound coming from the fixtures.   This is not good for a sound sensitive room!  I double checked the fixture submittals and no mention of sound generation was found.  This particular fixture included a vibrating diaphragm, which dissipated the heat away from the LEDs, and this was the source of the observed sound.  With 32 of these fixtures in the space, you can imagine the volume of the humming!

Viable Solutions

With the help of the electrical contractor and the manufacturer’s rep, the fixtures were successfully replaced with a similar LED fixture without the vibrating diaphragm. In my experience, most manufacturers are thankfully not using this vibrating diaphragm to dissipate the heat in high lumen LED fixtures and have found alternate methods.  Nevertheless, this detail remains something engineers should verify for these types of applications.

Although LED fixtures are here to stay, it’s important to remember that any new technology will have some bugs to work out. As illustrated above, engineers need to do some extra homework when specifying LED fixtures in different applications and space types.

Click here to see other projects where Allegheny Design Services is helping provide efficient lighting for our clients.

Written by Mike Chancey, PE, LEED AP, MEP Department Manager

mike-chanceyMike Chancey is a native of West Virginia. He grew up in Hurricane and is presently residing in Bridgeport. Mike graduated from the West Virginia Institute of Technology with a bachelor’s degree in electrical engineering. After a brief two year stint with Duke Power in Greensboro, NC, Mike spent the rest of his career designing electrical systems for various building types and facilities. Mike is a member of the Clarksburg Kiwanis Club and active in community service work in Harrison County as a board member of the Harrison Co. YMCA and current president of the board for Empowerment through Employment.

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