Cooling plant along the M1, M25 and A1(M)
Hertfordshire's wet cooling is spread out rather than clustered. The big distribution parks off the M1 and M25, such as the Maylands area of Hemel Hempstead and the sites around Hatfield and Welwyn, often have cold stores and chilled warehouses with evaporative condensers on the refrigeration plant. Stevenage and the towns along the A1(M) have a strong life sciences and engineering presence, with lab buildings that need steady temperature control. Add hospitals, college and university campuses, and office buildings in Watford and St Albans, and there's a lot of plant across the county.
Evaporative condensers on cold stores
Evaporative condensers are easy to overlook. Site teams tend to call it "the condenser on the cold store" rather than a cooling tower, but it carries the same Legionella risk and the same duties: it must be notified, treated, monitored and cleaned. Our article on towers versus condensers explains why.
A few things make them trickier than a big tower. The water volume is small, so biocide and inhibitor levels move quickly and a dosing hiccup shows up fast. The coil runs hot, so in hard water scale can build on the tubes within weeks if bleed falls behind. And they often sit beside loading bays or yards where drivers wait with their windows down, which puts people right in the path of any drift.
Chalk water, consistently hard
Affinity Water supplies most of Hertfordshire, and a large share of its water comes from boreholes in the chalk. The result is hard water that tends to be fairly steady through the year. That steadiness is useful: once a bleed setpoint is right, it tends to stay right. The hardness itself still means conservative cycles of concentration and an inhibitor chosen to suit. A few fringe areas are supplied by neighbouring companies, so check with yours. If your site tops up from a private borehole instead of the mains, that water can be quite different and needs its own analysis before we set anything.
Getting on site
From Chiswick, most of the county is a straightforward run up the M25, M1 or A41, so regular visits are easy to keep to. Distribution sites bring their own rules: booked arrival slots, yard marshals, hi-vis, reversing lorries, and plant reached by ladder onto a gantry or the flat roof over the cold store. We do the site induction, stick to agreed walking routes and keep our van where the yard team wants it. Lab and hospital sites usually want RAMS and COSHH information in advance, which we send ahead of the first visit.
Who to notify in Hertfordshire
Hertfordshire has a county council and ten district and borough councils: Broxbourne, Dacorum, East Hertfordshire, Hertsmere, North Hertfordshire, St Albans, Stevenage, Three Rivers, Watford and Welwyn Hatfield. Environmental health sits with the district or borough, not the county, so that's who you notify under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992. Your local council's environmental health team will have the form.