Mounting Operating Room Lights with Structural Steel Support Structures vs. Unistrut

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In addition to material sales, we do a fair number of Unistrut installations to create overhead support structures for operating rooms.  OR installations are particularly well-suited for Unistrut because we can build support structures without welding.  Welding creates explosion risks due to the presence of oxygen tanks and pulling burn permits is a no-no. This process also creates fumes and dust that contaminate sterile areas.  Medical installations also require the fabrication of overhead structures to support and precisely position equipment that can exert loads ranging from hundreds to thousands of pounds.  For all these reasons, Unistrut is often the material of choice when fabricating overhead support structures for hospital applications.  With this said, we routinely see inadequate support structures fabricated from structural steel that add cost and complexity to operating room remodeling projects.  Our recent visit to a major hospital in the Columbus, Ohio area is case in point.

A medical equipment manufacturer recently invited us to assess an OR support structure as part of a lighting update project.  Hospital officials hoped to use the existing support structure, but the equipment reps were concerned that the support structure’s suitability since the previous steel contractor failed to use any sort of bracing and the finished installation lacked engineering drawings.  In cases like these, lighting manufacturers are concerned about two issues:

  • Is the support structure strong enough to withstand the loads created by the equipment?
  • Is the structure engineered properly to prevent boom drift, which can cause internal clutches to fail prematurely, creating major nuisances for surgical staff?

With this in mind, how does one assess a support structure’s suitability?  One course of action is to engage a structural engineer to analyze the existing structure, measure welds, determine steel sizes, and prepare a report on the findings.  This process is very time consuming and comes at great expense because you are paying for the engineer’s time and you need to shut down the OR to perform the assessment.  You also need to provide sufficient space (typically larger than the holes that were cut for the access panels) to allow a person to perform the appropriate measurements.

To complicate matters further, in a best-case scenario, your structural engineer may verbally claim that the support structure seems adequate, but without the drawings, he or she won’t put anything in writing—if your equipment fails, the manufacturer will claim that the support structure was to blame.  In a worst-case scenario, your engineer is likely to find that the support structure is in need of modification to handle the loads, and since structural steel was used during initial fabrication, adding reinforcements means additional welding. By using a PRO 3600 digital protractor digital protractor, we were able to measure the actual plate/structure rotation under actual load in four rooms without enlarging the existing access panels:  OR 1, OR 3, OR 8 and OR 2. The structures in OR 1 and OR 2 appeared similar in construction, as did OR 3 and OR 8. Both “types” were welded structures, and are not a modular structure that allows modification without welding.   To perform each test, we placed both existing light heads at one end, and rotated smoothly 180 degrees, while measuring the rotation with the digital protractor.

OR Lighting System Support Structure

Most medical equipment manufacturers, including Steris, Stryker, Skytron, and Berchtold just to name a few, allow for a maximum of .2 degrees rotation under load, but upon careful inspection, the values exceeded recommended tolerances.  Actual rotation per our testing is shown below.  Please note that we are giving two readings per room, one “North-South” and one “East-West”:

  • OR 1: .4 degrees and .28 degrees
  • OR 3: .68 degrees and .24 degrees
  • OR 8: .47 degrees and .07 degrees
  • OR 2: .46 degrees and .73 degrees

As you can see from the measurements above, only one of the eight runs fell within the recommended tolerances. Based on our findings, hospital administrators have a difficult decision to make:  modify the existing support structure, which will require additional welding, or start from scratch with a modular structure made from Unistrut channel. Unfortunately, we see situations like this on a frequent basis.  In many instances, low bid structural steel fabrications, some less than 5 years old, need to be scrapped because the support structure will void the manufacturer’s warranty on the OR lights.  To make matters worse, assuming that the existing structural steel support system does meet with the manufacturer’s specs, any re-configuration of the operating rooms that requires moving lighting requires additional welding and fabrication in a hospital environment.  Put another way, the original cost of the support structure, combined with an engineering assessment and subsequent demolition of the old installation far exceeds the price tag associated with building with Unistrut from the start of the initial project.Before you begin your next project, remember to ask yourself a couple of key questions:

  • What critical tolerances must be held?
  • Will failure to meet these specifications have any adverse effect on equipment?
  • What construction methods are appropriate given the installation environment?
  • Is welding safe?  Is it practical?
  • What is the expected service life of the installation?
  • Would remodeling of the room require modifications to the support structure?
  • Will your contractor supply finished engineering drawings?

Taking care to review this list of questions prior to beginning work on your overhead support structure will help you steer clear of additional costs and headaches down the road.  To learn more about overhead support structure for medical applications, our company capabilities, or to request a quote, contact Unistrut Service Company for more information.