Why mercury float switches are being replaced
For decades, mercury float switches were widely used in water tanks, pumping systems, and level control applications due to their reliability and precise liquid level monitoring. However, with increasing awareness of environmental and safety risks associated with mercury, the industry has shifted toward safer, more sustainable alternatives. Today, non-mercury float switches, such as T-T Pumps FLO Series, have become the preferred choice for both domestic and industrial systems.
Mercury is a toxic heavy metal which is dangerous to your health and creates hazardous effects in the environment. In classical float switches, conductive liquid mercury was used to complete electrical circuits as the float tilted to new positions. While highly effective, exposure risks during disposal or damage made these switches unsuitable for modern safety and sustainability standards.
Strict measures on the use of mercury in industrial and electrical components have been instituted by environmental regulators such as the UK Health and Safety Executive (HSE) and the European REACH legislation. The Mercury Convention, the World Environmental Convention and the Minamata Convention on Mercury limit their application further to avoid polluting water sources.
The combination of these regulatory demands, together with the development of sensor technology, has helped to shift to non-mercury float switches, which offer all the functionality and none of the danger.
Modern alternatives
Non-mercury float switches have environmentally friendly elements like micro-switches or rolling balls to measure water levels. These are enclosed within buoyant housings, typically made from polypropylene or other corrosion-resistant plastics, ensuring durability in varied water conditions.
The FLO Series Float Switches of T-T Pumps is an example of this new ethos of a mercury-free design. Their key features include:
- Mercury-free operation: They rely on rolling a ball or activating control circuits with a microswitch that is safe.
- Strong materials: The housings are moulded with strong polymers that cannot be easily affected by water or chemicals.
- Broad area of use: They can be used in sewage systems, sump pumps, floods, and clean water tanks, diesel and fuel oil systems.
- WRAS certifications: They are certified for use in drinking water systems (as on the FLO107 model).
Although the mercury-based switches in the past had been known to be precise and simple, they fail to meet the present safety, sustainability, and compliance standards. Their drawbacks include:
- Ecological hazard: Mercury leakage is a long-term ecological risk, which pollutes water and soil.
- Disposal compliance problems: Mercury switches should be disposed of by specialists to avoid polluting the environment with hazardous waste.
- Residual certification compliance: WRAS and NSF standards prohibit the use of mercury in systems that are used to treat potable water.
- Health hazards at work: There are chances of accidental breakage during maintenance, exposing the operators to toxic vapours.
The water industry in the UK, in accordance with the best environmental practices, currently requires non-mercury in new installations, as well as in retrofits.
Mercury float switches have played their part in the evolution of water control technology, but they are now being phased out in favour of safer, compliant and sustainable alternatives. T-T Pumps UK-manufactured FLO range represents the next generation of water level management, rugged, precise, and entirely free from hazardous substances.
