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John Muir Medical Center Meets Mechanical Specs Thanks to Aeroseal

Ranked as one of the top hospitals in the country, John Muir Medical Center is a showcase for excellence in everything they do – from medical care to building design and construction best practices. When they decided to turn existing space of the building’s 2nd floor into a new endoscopy surgery unit they decided to repurpose the existing mechanical system serving the space. Pretesting, however, indicated inadequate airflow, resulting in unacceptably low levels of exhaust throughout the unit.

In Brief

  • Building: John Muir Medical Center
  • Location: Walnut Creek, California
  • Engineer of Record: Mazetti Inc.
  • General Contractor: Swinerton Builders
  • Aeroseal Provider: Air Seal Solutions
  • Goal: Improve airflow through leak reduction
  • Before Aeroseal: 1,583.4 CFM of leakage
  • After Aeroseal: 222.1 CFM of leakage
  • Results: Aeroseal eliminated 1,361.3 CFM of leakage – an 86% reduction.

When further investigation indicated that the limited airflow was due to duct leakage, the mechanical contractor on the project suggested they use aeroseal duct sealing to shore up the leaks with minimal disruption. Hospital concern that the aerosol-based sealant could damage sensitive equipment was eliminated when the aeroseal pros used their clean-room mitigation expertise to monitor the air quality of the space during the duct sealing process.

A mechanical team taped the leaks around the easy-to-access portions of the ductwork – where the ducts connected to the registers. Shortening portions of the ductwork also helped alleviate some of the airflow problems caused by poor design. To eliminate the majority of leakage, located in the hard to access sections of the ductwork including the exhaust riser and lateral connections, Aeroseal proved to be the only viable option available.

It took Air Seal Solutions just a single weekend to aeroseal the two designated sections of highly inaccessible ductwork. In the end, 1,583.4 CFM of leakage in theses sections was reduced to just 222.1 CFM – a 86% reduction. During the entire process, testing showed airborne particles of sealant remained well below ISO 9001 levels.


The technology worked. If you have an existing mechanical system that is ten or twenty years old, you can make it like new again – give it new life – by using aeroseal technology…We are planning to convert a number of buildings into doctor suites and I can see aeroseal technology being a viable solution when it comes time to rehabilitate the existing ductwork. In new construction, it can be used to seal the entire duct system once it’s been installed.”

Peter Spadia
Project Manager
John Muir Medical Center

Aeroseal duct sealing allows us to easily seal leaks in existing ductwork. It is particularly valuable when leaks are otherwise hard to reach– behind walls or other obstructions. I recommended that it be used on this project and would recommend its use for most retrofit projects where existing ductwork is being repurposed.”

Patrick Grubb
General Contractor
Swinerton Builders

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