What you need to know about UVT when selecting a UV system

What is UVT:

UVT – Ultraviolet transmittance – is one of the most important performance parameters to consider when selecting a UV system for your application.

  • UVT is a measurement of the UV energy, at precisely 254 nanometres wavelength, that passes through the water column.
  • UVT is usually expressed as a percentage, with a higher number corresponding to ‘clearer’ water, which allows more penetration of UV radiation for the deactivation of pathogens.

‘Clearer’ doesn’t necessarily mean clear to the eye.

Some UV-absorbing chemicals appear transparent but can drastically reduce the UVT of water!

When selecting UV disinfection for any application – whether potable water, rainwater harvesting, wastewater, or water reuse – it is most important to understand the UVT of your source water and any seasonal or other changes that might affect the effectiveness of UV disinfection.

This is especially important for surface water sources where spring runoff, heavy rain, falling leaves, and airborne debris such as pollen can have a major impact on water conditions.

UV Pure’s products are validated to provide an effective UV disinfection dose in water with UVT as low as 50%.

This level of treatment assures public health protection under challenging conditions and is significantly better than many conventional UV systems, which are often rated to be effective for cleaner water at UVT above 75%.

UV Pure systems can achieve this level of treatment because Crossfire Technology® incorporates a dual-lamp, reflective disinfection process that provides 2.4 times the dose of conventional light-in-a-pipe systems and targets pathogens from 360 degrees to eliminate shadowing. Each unit is also equipped with a self-cleaning system that prevents fouling of the quartz sleeve from minerals and enables it to be effective in water 10 times harder than conventional systems.

How Crossfire Technology® works:

What to check when restarting UV Pure units for seasonal water systems

Are you getting ready to restart a UV Pure system at your seasonal property? Each UV Pure system is designed to make restart a simple process – almost as simple as flipping on the power and opening the water valve. To ensure optimum performance of your system, seasonal startup is a good time to perform a few simple inspections.

Before restarting your UV Pure system:

  1. Inspect the quartz sleeve for cracks, breaks and fouling.
  2. Inspect the reflector panels for damage.
  3. Inspect lamps for cracks and breaks.
  4. Inspect quartz around the filaments for discolouration at the ends, which indicates a bad lamp or a possible ballast issue.
  5. Reconnect all fittings and close all valves.
  6. Slowly apply water pressure and inspect the unit for any signs of leaks or loose plumbing joints.
    • If any components in steps 1 to 6 require attention, consult your manual or contact a qualified UV Pure service representative.
  7. When the system is fully pressurized, turn on the UV Pure system and allow the lamps to reach full power. This may take up to 24 hours.
  8. Once operational, flush water through the unit for at least five minutes.

Importance of having UV lamps:

We recommend making spare lamps available at each site to ensure uninterrupted system operation. UV lamps have a limited lifespan and should be changed after 12,000 hours of operation.

Your UV Pure system will alert you when:

  • the lamps require changing as they approach end of life, or
  • when lamp output has dropped below the optimum operating level. A menu screen in the LCD display of Hallet® and Upstream™ systems also shows the remaining lamp life.

Whenever changing lamps:

  • use only genuine UV Pure lamps to ensure the system meets certified performance standards and to avoid adverse effects to sensitive electronic components.

To understand all the benefits of using genuine UV Pure lamps, read this post.

For more information about restarting UV Pure systems, please see your instruction manual.

To order spare lamps or other parts, or to arrange for service of your UV Pure system, contact your local UV Pure service provider.