Hospital Blocked sewer alarms


The Challenge

The switch to disposable pulp-based hospital trays, bowls, and bedpans was seen as a way of reducing the risk of contamination within healthcare. However, rather than incineration, many hospitals, and healthcare facilities are now macerating and flushing potentially hundreds of millions of trays, bedpans, and dishes complete with their contents down the sewers.

According to the leading manufacturer of these pulp products and macerator machines virtually any form of body fluid can be collected in these pulp containers, macerated, and flushed without sterilisation!

As the sewage-laden pulp is likely to be less dense than water, the first thing to spill if there is a blockage, surcharge, overload or clogged sewer is likely to be this contaminated waste pulp with its potentially deadly cocktail of biological and chemical contaminants.

Our Solution

By installing RDN’s BDT sensors below the manholes within a hospital and its grounds, it is possible to detect the onset of a blockage in main sewer lines early before a clogging incident becomes a disaster. Reports abound of the costly ward and theatre closures that potentially could have been averted with x-ray vision into the sewers under the hospital’s floor.

The BDT may not be an X-ray machine but it is a multi-award winning UK-designed and manufactured battery-powered sensor unit that looks for a high level in the sewers. Installed without the need for power and messy cable runs, the BDT’s ultra-low power wireless signal emerges clean through manhole covers and can be used to trigger an audible sounder, or beacon and/or can be repeated within a building over significant distances to a Gateway connected to the hospital’s existing building management system (BMS).

The BDT is an industry-proven design first introduced in 2010. Features include a 10-year battery life, ATEX certification, and the ability to withstand 100% submersion as standard. The BDT is also supplied with a cable settable probe that permits the alarm point to be adjusted from as little as 18in (50cm) to 15ft (4.6m). Units capable of servicing sewers up to 25ft (7.8m) can also be supplied to special orders and Gateways can interface anything from a single BDT to up to 64 to a single BMS outstation all via simple volt-free relay contacts.

The BDT is also suitable for use as a wet well sump alarm and basement flood alarm. One system offers a wide range of solutions.

To find out more, call us at 01279 600 440 or email


Sales & orders

Please call your local distributor for prices on products, systems and solutions. Spares and accessories may also be purchased through our online web portal