Accelerated Aging Chamber, Part 2

Troubleshooting

Conservation Intern, Associate Conservator, and Project Conservator working to troubleshoot an issue with the water purification system that occurred while this post was written. AMNH/F. Ritchie

Part 1 of our posts on accelerated aging instrumentation introduced the Q-SUN Xe-3 accelerated aging chamber. In this posting we describe some of the challenges we have experienced in installing and operating the machine; challenges which were unexpected and eye-opening. Problem-solving these situations has been such an important learning experience for us, demonstrating what taking on a project of this magnitude really entails.

Modifying the Lab

Our initial challenge was retrofitting the lab to accommodate the needs of the unit. In addition to electrical and plumbing adjustments to provide sufficient voltage, surge protection, purified water, and condensate drainage (all while retaining the ability to move the unit around the lab on its casters as needed), we had to install a ventilation hood over the machine with a fan and ductwork to vent its exhaust directly out of the building. This was necessary to limit the machine’s impact on the environment in the lab and adjacent offices, which otherwise became uncomfortably hot and cold respectively. The improved ventilation also allows the machine to cool itself much more efficiently, reducing both the noise and overall consumption of purified water – saving both our budget and our ears. We learned firsthand how important it is to moderate lab temperature when the HVAC system in the lab randomly failed and the machine was forced to stop because the chamber air rose to an unacceptable temperature. Luckily our maintenance staff provided the troubleshooting for this situation and the test cycle resumed within 24 hours.

Lesson: Make sure to understand completely the needs of a machine and its impact on day-today processes.

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Ventilation hood and fan installed above the Q-SUN Xe 3 chamber to extract heat generated from the machine, helping maintain lab temperature. AMNH/F. Ritchie

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New ductwork installed to direct exhaust from the Q-SUN out of the lab. AMNH/F. Ritchie

Setting Test Parameters

Our next unexpected hurdle was in setting our testing parameters inside the Q-SUN (i.e. the RH, chamber air temperature, and irradiance). Our previous dye testing was undertaken following the ASTM D4303 (Method C) testing standard in a chamber that did not have the capacity to control for RH. Because our Q-SUN Xe-3 chamber can be run with RH control, we initially chose a different standard ASTM D4303 (Method D). Immediately, to our horror, we found that condensation was forming inside of the machine, dripping onto the carefully prepared samples and making them unusable.

Initial troubleshooting with Q-Lab Corporation (the Q-SUN manufacturer) focused on possible problems with sensors or calibration within the machine, but that did not solve the condensation problem. Ultimately we learned that the D4303 test Method D is outside the capabilities of the Q-SUN Xe-3 (and apparently outside the capabilities of any humidity controlled xenon arc testing chamber). This was not an intuitive conclusion since Method D is specifically written for a Humidity Controlled Xenon Arc Device. As such, we have adjusted our test parameters so that they now lie well within the capabilities of the machine, and more closely replicate the Museum’s diorama conditions that we are chiefly concerned with.

Lesson: Understand that standards are often simply guidelines to follow to provide consistent parameters for comparison. Standards can (and often, should) be adapted to meet necessary requirements.

Dealing with Malfunctions

The most recent wrinkle in our operation of this machine was the spontaneous cracking of one of the UV-blocking filters that we are using for half of the testing rounds. Though this required us to suspend our testing for a few days, Q-Lab Corporation was very quick in providing a replacement, and since then we have been able to run the unit without incident.

cracked filter with arrow

Crack in a portion of the glass UV filter. AMNH/F. Ritchie

Lesson: Be flexible and ready to deal with unforeseen circumstances, and maintain a good relationship with the manufacturer of your equipment.

Budgeting for Consumables

The Q-SUN Xe-3 requires air filters, water purification filters, replacement lamps, sample preparation supplies, and many other expendable items that add cost beyond the initial purchase of the machine. Our grant budget has been adequate to deal with consumable materials, but we have realized that we must be prudent when running the machine and we must stay on top of ordering replacement supplies. There are even differences between test cycles. We are finding that our UV-filtered test cycles use up the lamps and water filters more quickly than the UV-rich test cycles.

Lesson: Pad your budget for expendable supplies and be sure to order the next set of replacements as soon as you install the first set.

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Row of Q-SUN replacement lamps awaiting installation. AMNH/F. Ritchie

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Project Conservator replacing a lamp. AMNH/J. Sybalsky

CONCLUSION

Owning and operating an accelerated aging chamber, at least one as complex as the Q-SUN Xe-3, is more than a plug-and-play operation. We hope that the steepest part of the learning curve is now behind us, but past experiences have taught us to expect that new issues will present themselves as we continue to work with this machine.

Lesson: When using any new tool or taking on any new experimental analysis, be sure to build time into the project timeline for troubleshooting.

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