Manufacturer and supplier of roof products and accessories for the metal building industry since 1964

Smoke Vents – Operable vs. Melt-Outs – Which is Best?

October 23rd, 2017 | Eric McClung

Product Comparison – Smoke Ventilators

When evaluating operable smoke ventilators versus melt-out units, architects, builders and contractors should weigh the pros and cons of each before making a decision.

Components to consider include:

  • The service life of the unit
  • The safety of maintenance personnel and fire response teams
  • The cost to purchase, install and maintain the units for reliable performance


ExoVent Solar - Heat and Smoke Escaping
Rendering of Heat and Smoke escaping from ExoVent™ Solar


R&S has been in the business of manufacturing and selling UL 793 rated smoke vents for over 25 years. We’ve carefully weighed the options and here is our conclusion:

  1. Operable smoke vents are reusable and can be tested to ensure proper performance. There is no real way to test a melt-out unit. In addition, operable smoke vents can be opened without consuming the fusible link assembly. This is particularly helpful if ventilation is required in a pinch.
  2. Fire Marshalls prefer a fusible link approach for several reasons. One key reason is in the event of a fire, they do not want the risk of hot plastic dripping from the ceilings while crews are inside the building suppressing a fire. Hot dripping plastic can also adversely impact the performance of sprinklers located just below. In addition, operable units can be opened to improve visibility within the building by allowing smoke to exit even if the fusible link has not been activated. This is done via manual or remote release.
  3. Melt out units tend to have poor uplift ratings. Moderate winds can act to compromise the seal and may result in leakage. R&S manufactured UL smoke vents have been tested to withstand 30 PSF which equates to 108 mph uplift. We also offer a high-uplift model which is rated at 90 PSF or 187 mph.
  4. Our hatches use fusible links which can be coordinated with the sprinkler head activation temperature. With melt-outs, the units will likely be consumed (partially or completely) without cause. In the event the fusible links do release, they are easy (and very cost effective) to replace.
  5. Despite all the benefits of an operable smoke vent, pricing is relatively the same. So quite simply, operable units offer more value at essentially the same cost.

In our opinion there is NEVER a case in which melt-out units should be selected over operable smoke vents. We offer among the largest assortment of UL tested and approved Smoke Vent sizes in North America. We also offer High-R value smoke vents for cold storage buildings AND high-capacity applications for areas that are susceptible to snow loads. Units come fully assembled and ready to install and require very little to no configuration on site.

Check out our full line of ExoVent™ Smoke Ventilators here.


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