Condensation Reduction

Security camera report: Protective vents vs. desiccants

When condensation forms inside a security camera, it can blur lenses and compromise image quality. Condensation that remains within the enclosure can also corrode electronics, causing premature failure of the camera. Gore compared two IP66-compliant methods for reducing condensation: desiccant within a sealed camera enclosure, and a protective vent installed in an identical camera. Results showed that the protective vent was significantly more effective at dissipating moisture over time. The vent also protected the enclosure from seal failure and subsequent water ingress.

There are several conditions that will promote the formation of condensation within a sealed security camera enclosure. These include exposure to frequent or heavy rains, exposure to large daily temperature swings, sudden temperature changes due to extreme weather, and repeated pressure differentials that stress seals to failure, allowing moisture ingress.

Historical Approaches to Reduce Condensation

Initially, an open diffusion port (through-hole) in the camera enclosure was viewed as a cost-effective way to dissipate interior moisture. These ports, which readily allowed ingress of contaminants such as dust, sand, water and other liquids, could not meet today’s IP66 standards for ingress protection.

Subsequently, sealed camera enclosures were adopted to meet IP66 requirements. Since the sealed environment itself promoted the formation of condensation, desiccant packs were introduced before sealing the enclosure. However, desiccant packs have a limited effective life, and end-users must periodically replace them. This can be time-consuming and costly, due to the installation height of most outdoor security cameras.

Alternatively, a GORE protective vent can be installed over a throughhole in the enclosure. The GORE vent provides IP66 protection against ingress of particulates and liquids, while rapidly equalizing pressures, and reducing condensation, within the enclosure.

Vent Technology

These vents incorporate the proprietary technology of the GORE membrane. Its microporous structure allows bidirectional passage of gas and vapor molecules, while blocking ingress of particulates and liquids.

Made of 100 percent expanded polytetrafloethylene (ePTFE), the chemically- inert GORE membrane is resistant to virtually all acids, alkalis and detergents. It is also highly resistant to UV degradation, for extended service life in outdoor applications.

The Study Methodology

Two identical outdoor security cameras were purchased. One camera was left in its original state: sealed, with a desiccant pack inside. For the other camera, the desiccant pack was removed and an adhesive vent was installed over a through-hole.

Both cameras were mounted within a climate chamber, with each camera powered and connected to the network under manufacturer-recommended operating conditions. Each camera was focused on, and equidistant from, its own target image.

Two separate climate chamber tests were performed:

  • Test No. 1 compared image quality and humidity levels within the two camera enclosures.
  • Test No. 2 compared the effects of harsh conditions on the two camera enclosures, and the related effects on camera function and reliability.

Climate Chamber Test #1: Comparative Image Quality and Humidity Levels

This test employed a temperature and humidity cycle extending from -15 °C / 0 % RH to 55 °C / 85 % RH. This cycle incorporated a 10-minute water shower, to simulate rain.

Over the course of eight such cycles, we recorded images from each camera, as well as the humidity inside each camera enclosure, in order to monitor the levels of condensation.

As for image quality results, images captured during multiple subzero periods demonstrate a dramatic difference in clarity. Image quality from the camera with desiccant continued to degrade, as more condensation formed on its lens with each cycle. By Cycle 8, the image is significantly blurred. Image quality from the camera with the vent remained much more consistent, because it did not experience a similar accumulation of condensation.

The recorded comparative humidity levels within each camera enclosure also showed important differences. While humidity within both enclosures increased in response to climate chamber conditions, the camera with desiccant shows a significant increase, beginning at Cycle 6. This is because the desiccant moisture-absorption process reverses itself after several cycles of high humidity. At Cycle 6, the desiccant was fully saturated and began releasing water back into the camera enclosure, creating the condensation it was intended to combat.

Climate Chamber Test #2: Camera Reliability Under Harsh Conditions

The objective of the second test was to compare the performance of the two cameras under harsh conditions. The results were examined in terms of their effect on the camera’s function, as well as their implications for camera reliability over the long term.

For Test #2, the climate chamber was set up to reflect more challenging environmental conditions. A 10-minute water shower was applied twice daily to each camera enclosure, to simulate rain or pressure-washing. The chamber remained at a constant temperature and relative humidity of 55 °C / 85 percent RH throughout this 10-day test. During the 10 days, humidity levels remained consistent in the camera with the vent. In the sealed camera with desiccant, humidity accumulated quickly over the first three days, and jumped dramatically on the fourth day. From Day 4 onward, the sealed camera with desiccant experienced serious condensation, with related degradation of image quality.

To understand the dramatic “Day 4” jump in humidity, it is useful to examine the corresponding pressure and humidity data for that camera.

After Day 2, pressure differentials in the sealed camera diminished dramatically. Subsequent examination showed that the strong initial pressure differentials had stressed the seal to the point of failure.

The subsequent temperature drops created negative pressure within the enclosure, drawing ambient air and shower water in through the failed seal. The desiccant could not counteract this trapped moisture. Thus, excessive condensation formed on the lens, seriously degrading the image quality.

Of greater concern are the large fluctuations in internal pressures that are produced in totally sealed, for example, non-vented, camera enclosures. Such pressure fluctuations cause severe and repeated stress on seals, leading to premature seal failure. This in turn allows ingress of external contaminants and water, and accelerates the formation of condensation. This will degrade image quality, and promote corrosion of sensitive electronic components. Either or both of these conditions will negatively impact the performance reliability of the camera.

Our tests demonstrate the performance advantages of incorporating a GORE protective Vent in security camera enclosures. Results show the GORE vent, which provided IP66 level protection against water and environmental contaminants, dissipated moisture much more effectively than the sealed enclosure with desiccant. By reducing the severity and duration of condensation events, the vented camera enclosure continued to deliver consistent image quality and clarity over time. The likelihood of condensation-induced corrosion damage was correspondingly reduced.

Additionally, the vent provided superior response to pressure differentials caused by changes in ambient conditions. Within the vented enclosure, pressure fluctuations were rapidly equalized, minimizing stress on seals and the chance of premature seal failure.

By protecting the camera’s image quality and the enclosure’s seal integrity over time, the installation of a protective vent can effectively enhance the long-term reliability of a security camera.

This article originally appeared in the April 2015 issue of Security Today.

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