Technical Update Bulletin BA#21: September 2020
Testing Access Panels for Air Tightness and Exposure to Cleaning Agents - Critical to Infection Control
Results: "BAUCO® access panels are considered hermetically sealed and able to withstand long-term exposure to harsh cleaning chemicals"
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More than ever, architectural, engineering, and construction professionals are involved in creating healthcare facilities and other work spaces which allow us to live in a pandemic and post-pandemic world. Standards and approaches have to change to address the safety of occupants. Access panels and grilles are parts of the built environment and therefore this article will review how our products and testing processes contribute in this context. Under consideration here are BAUCO® plus II access panels and BAUCO® air grilles for return air.
BAUCO® is in the business of creating access panel and grille solutions which minimize the disruption of surfaces and maximize the functionality of access openings. Our basis of product design is an access panel without hardware components that extend above the finished surface of walls or ceilings. This flush hardware, by design, minimizes opportunities for surface contamination and the accumulation of pathogens.
The BAUCO® Technical Services Department has developed a number of product testing protocols in the context of infection control measures. Laboratory installations mimic conditions under which our products have to perform in the built environment. One test focussed on air tightness of access panels in clean rooms and differential pressure environments. Another test examined the exposure of access panels to common chemical cleaning agents used for surface cleaning and disinfection. We also sourced and evaluated the specialized powder-coating material “Sterilcoat” for application to aluminum frames and grille cores. Here are some of the highlights.
AIR TIGHTNESS TESTING
To get an understanding of how the BAUCO® plus II access panel performs in an application where preventing air leakage is a design factor, we conducted in-house testing according to ASTM Standard E283. Essentially, a pressure differential is created across an assembly containing an access panel. The pressure differential intervals of 50, 100 and 200 Pascals are common measurement points for conventional air leakage tests. For a standard BAUCO® plus II access panel (touch latches, gypsum board inlay, aluminum frame and EPDM gasket) we have determined the following:
Optional Features: Air tightness testing of BAUCO® plus II access panels with optional keyed locks showed a 20% decline in the performance, but this is still within the range that qualifies as "hermetically sealed".
Although explicit industry standards are elusive, an article in a cleanroom industry publication states: “What level of appropriate air tightness should the door have? 3,5 m3 / hm2 measured at 200 Pa pressure is a reliable and good value”. Source: https://www.cleanroomtechnology.com/news/article_page/How_to_choose_the_right_cleanroom_door/142239
Conclusion: Looking at figures for similar products (entry doors for cleanrooms) BAUCO’s in-house testing results of 3.145 (3.212) m3/m2/h are within what is considered to be a hermetic (i.e. airtight) seal for clean room applications.
Future Air Tightness Testing:
The BAUCO® Technical Department is considering some further air leakage testing to expand our information repertoire. These will include:
- Independent laboratory verification of above results
- Air tightness testing of other access panel models
- Evaluation of possible long term decline of EPDM gasket performance after 30 days or more
- ASTM E90 STC testing of selected models which may provide insights into air leakage
EXPOSURE TO CLEANING AGENTS TESTING
To date, we have exposed the BAUCO® plus II hardware (frame, gasket, latch hardware) to four of the most common medical cleaning agents (quaternary ammonium, hydrogen peroxide, isopropyl alcohol and sodium hypochlorite (bleach)). The parts were sprayed for a minimum of 360 clean-dry cycles. Assuming a medical environment sees two clean-dry cycles per day, this equates to six months of field use.
Results: The critical piece – the gasket – has remained largely unaffected. No embrittlement or degradation of the gasket has been observed yet, which would indicate that the gaskets ability to provide a seal has been maintained. Given this, we can also infer that the hardware on the other side of the gasket would be protected from corrosive chemicals. Only the tests using hydrogen peroxide and sodium hypochlorite exhibited some corrosion on the aluminum extrusion and the hardware – though the hardware remained fully functional. This could however be mitigated by painting these components in the field, or by powder coating the outer frames for use in these harshest applications.
Conclusion: BAUCO® plus II access panels perform well under heightened (2x daily) cleaning routines with common commercial cleaning agents and disinfectants. BAUCO® has the know-how and facility to powder-coat access panel components for even harsher conditions and is able to evaluate any other concerns in its Technical Department. Please inquire!
ALUMINUM EXTRUSION TREATMENT TO MITIGATE PATHOGEN ACCUMULATION
Standard access panels have a mill finish aluminum frame. Once installed and finished, the exposed surfaces receive a paint coating as part of the finished wall or ceiling assembly. We wanted to further address the possibly harmful pathogen accumulation on the access panel frame. Particularly, we considered the 1/16” (2mm) gap between frame and door leaf which is sealed by the gasket. To do so we have trialed a specialized powder coating compound (“Sterilcoat”) with which the metal components of the access panel can be coated. According to the manufacturer, this product is proven to decrease the presence of microbes by 99.99% after 24 hours.
The powder can easily be applied to our frames using BAUCO® ’s conventional powder-coating line. Please inquire with your requirements!
With regard to the performance of this finish compared to bare aluminum we can make the following observations. The compound allows for a solid bond with drywall mud along with a strong barrier to corrosion of the aluminum. Long term testing is currently in progress to determine the effects on the coating in the event that it is damaged during installation (particularly sanding of the drywall during finishing).
FURTHER TESTING AND CERTIFICATION
BAUCO® will confirm selected results through certification by an independent testing laboratory in the months to come. In the meantime, you may be able to consider the above results in your designs / specifications.
TELL US: Are you designing/specifying environments in the time of COVID? Let us know your thoughts on our testing or any other applications you see for access panels and grilles in this context. We are in the business of creating solutions to your access panel and grille problems. BAUCO® ’s Technical Department is at you service.