Acoustic consultants in Oldham for noise surveys and BS 4142 assessments.

Oldham's noise climate is shaped by its history as a cotton-spinning town. Mills were built across Oldham, Chadderton, Royton, Shaw and Lees, and the ones still standing have mostly gone one of two ways. Some are being converted to flats, which brings sound insulation and facade noise questions into a structure that was built to carry machinery rather than separate homes. Others are in use as warehousing, storage and light manufacturing, often with terraced housing close on more than one side, and that is where much of the BS 4142 work in the borough arises: a long-standing source, homes that have always been there, and a new application that changes the hours, the plant or the yard.

The west of the borough carries the transport load. The M60 runs through Chadderton, Hollinwood and Failsworth, the A627(M) brings traffic in from the M62 and continues as the A627 into the centre, the A663 Broadway links the M60 to the A627(M) along the Chadderton side, and the A62 and the A671 Rochdale Road through Royton are the main radial routes. Broadway Business Park and the industrial estates around Chadderton and Hollinwood sit close to established housing, and warehouse and distribution sites in the borough can operate through the night. A residential scheme on this side of Oldham is usually dealing with a road source and a commercial one at the same time, and the assessment has to separate them: the commercial sound is rated against the background under BS 4142, while the road is assessed to ProPG and BS 8233 against internal and external targets.

Metrolink changed the town centre's sound. The Oldham and Rochdale line replaced the old railway loop and now runs on street through the centre, with stops at Oldham King Street, Oldham Central and Oldham Mumps, out through Shaw and Crompton towards Rochdale in one direction and Freehold, South Chadderton, Hollinwood and Failsworth in the other. Trams run early and late, they can squeal on tight curves, and on the street-running sections they pass within a few metres of upper-floor windows. The council's town centre regeneration is bringing new homes into the centre, close to the tram, so the tram is now a routine source in a noise survey in Oldham town centre rather than an afterthought. Heavy rail still matters too: the Huddersfield line runs through Greenfield and into the Standedge tunnel at Diggle, and the Calder Valley line passes close to the Chadderton edge of the borough.

Saddleworth is the other half of the borough and it behaves like a different place. Uppermill, Delph, Dobcross, Diggle, Greenfield and Denshaw sit in steep Pennine valleys with the moors above them, and at night the background sound level in these villages is very low. That is good news for residents and hard news for anyone proposing plant. A heat pump, a refrigeration condenser or an extract fan that would disappear into the traffic in Chadderton can be the dominant sound in Dobcross at three in the morning. Against a background that low, a quiet source can still show a large excess over background, and BS 4142 expects the absolute levels and the character of the area to be weighed as context. In a still valley that context can cut either way, so the report has to set it out rather than leave the outcome to the arithmetic. The valley sides also do unusual things to sound: a source part way up a hillside can be screened from the houses on the road below and clearly heard across the valley, and a propagation calculation that assumes flat ground gets the wrong answer.

Oldham Metropolitan Borough Council determines planning applications across the borough outside the Peak District National Park, and its planning policy now sits within Places for Everyone, the joint plan for nine Greater Manchester districts, alongside the borough's own development plan documents. Its validation requirements generally look for a noise assessment where new residential development is proposed near roads, the tram, railways or commercial and industrial uses, and where a noise-generating use is proposed near existing homes. Conditions on consents commonly require BS 8233 internal levels to be achieved in habitable rooms, a BS 4142 assessment of any fixed plant against the measured background, and a construction method statement with working hours where a site is close to neighbours. The environmental health team reads the reports, so the assessment has to answer the condition in the words it uses rather than in general terms.

The way we programme a noise survey in Oldham follows from that geography. A town or Chadderton site gets at least 24 hours of unattended logging with Class 1 meters, and several consecutive nights where the night background governs or where night-time deliveries or weekend trading matter. An exposed site on the Saddleworth moorland edge gets a longer deployment again, because more of the record is lost to wind and rain. We log the weather throughout and set the affected periods aside before the background level is fixed. Where a scheme runs from a busy road out to open country, as some of the borough's larger housing sites do, we measure at more than one position rather than carry one number across a site where it does not hold. The engineer who scopes the survey runs it, writes the report and answers the council's questions, so the person the officer speaks to is the one who was on site.