Nitrogen Purged vs IP68 Cameras: Waterproofing Guide
Beyond IP68: Why Nitrogen Purged Cameras Last Longer

Beyond IP68: Why Nitrogen Purged Cameras Last Longer

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↠Part of the Series: The Professional Sewer & Drain CCTV Handbook: 2026 Industry Edition

Beyond IP68: Waterproofing & Nitrogen Purging Explained

A drain camera lives its life underwater, often in corrosive chemical environments. The standard rating is IP68 (Immersion >1m). But IP68 is not enough for professional longevity.

Why? Because of Thermal Cycling. The camera gets hot (LEDs + Sensor). The water is cold. The air inside the camera contracts, creating a vacuum that sucks water past the O-rings. This is why we use Nitrogen.

The Science of Purging

Nitrogen Purging involves replacing the damp air inside the camera module with dry Nitrogen gas, pressurised to roughly 5psi.
Benefits:

  1. Positive Pressure: The internal pressure is higher than the outside water pressure (at shallow depths). If a seal is weak, gas leaks out; water doesn't leak in.
  2. No Moisture: Nitrogen is dry. There is no water vapour to condense (fog) on the lens when the temperature drops.
  3. Corrosion Inhibitor: Nitrogen is inert. It prevents oxidation of the delicate circuit boards.

The Maintenance Schedule

O-rings are rubber. They perish.
You must get your camera "re-purged" and re-sealed every 12 months. It's like an oil change for your car. If you see fog on the lens, it's too late the atmosphere is compromised.

Conclusion

IP68 is a rating; Nitrogen Purging is a protection system. Ensure your fleet maintenance includes annual pressure testing.

Recommended Gear

Why Professional Equipment Matters

In the field of utility surveying and safety, "cheap" equipment is arguably the most expensive mistake you can make. False readings leading to a cable strike, or a failed gas monitor in a sewer, can cost lives and millions in liability.

At Cable Locators & Survey, we stock only the verified industry standards Radiodetection, C.Scope, Abtech, and Leica. Every unit is checked, calibrated, and field-ready.

Troubleshooting Common Issues

1. Foggy Image? Check the Nitrogen

If your drain camera lens steams up after 5 minutes in a cold pipe, the Nitrogen purge has failed. The camera head needs to be re-pressurised by a service centre. Do not attempt to open the head yourself, as this invalidates the IP68 rating.

2. "No Signal" on Monitor

90% of signal failures occur at the termination point (where the coil meets the camera). This is caused by kinking the rod. Always use a "Saddle" or "Skid" to centralise the camera and reduce strain on the connection.

3. Blurry Recording

Ensure your lens window is scratch-free. Even micro-scratches scatter LED light, causing a "halo" effect. We recommend using a sacrificial plastic dome or "skid" to protect the sapphire glass.