A cooling water pump is not always a small automotive component - sometimes fitting in a mechanic's hand - that operates relatively quietly. In the context of various industrial facilities - such as chemical and petrochemical sites- it can also be a much larger piece of equipment that generates significant noise:
- regarding the working conditions of employees responsible for process supervision and equipment maintenance, with respect to the risks of hearing loss - which can be irreversible - as well as other risks, such as those associated with accidents caused by a failure to perceive warning signals (e.g. moving machinery, alarms in environments requiring specific preventive measures). European Directive 2003/10/EC concerning the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (noise) is a reference document, fixing:
- limit exposure values for workers to noise: exposure level L EX,8h = 87 dB (A) and peak sound pressure pcrête = 200 Pa or 140 dB (C) ref. 20 μPa
- lower exposure values for workers to noise triggering action: exposure level L EX,8h = 80 dB (A) and peak sound pressure pcrête = 112 Pa or 135 dB (C) ref. 20 μPa
- higher exposure values for workers to noise triggering action: exposure level L EX,8h = 85 dB (A) and peak sound pressure pcrête = 140 Pa or 137 dB (C) ref. 20 μPa
- regarding the neighborhood, in terms of the risk of nuisances - not only capable of disturbing the peace and quiet of residents but also of giving rise to litigation, formal notices, administrative sanctions, etc. French regulations, if applied, distinguish between the daytime period (7:00 a.m. to 10:00 p.m. except Sundays and public holidays) and the nighttime period (10:00 p.m. to 7:00 a.m. as well as Sundays and public holidays):
- in some cases, a prefectural decree (when it is not ministerial) sets the noise levels not to be exceeded at the property boundary: this is particularly the case for Facilities Classified for the Protection of the Environment (FCPE) e.g. 70 dB(A) during the day and 60 dB(A) at night
- emergence i.e. the difference between the equivalent continuous A-weighted pressure levels of ambient noise (considered industrial facility in operation) and residual noise (in the absence of the considered industrial facility, but measured over the period of operation of the considered industrial facility) is limited in the Regulated Emergence Zones (REZ), which generally include, near the considered industrial facility: homes, building zones and areas occupied by third parties e.g. Public Access Buildings (PAB), other industrial establishments. If the ambient noise level in the REZ (including the considered industrial facility noise) is between 35 dB(A) and 45 dB(A) then the admissible emergence is 6 dB(A) during the day and 4 dB(A) at night. If the ambient noise level in the REZ (including considered industrial facility) is greater than 45 dB(A) then the admissible emergence is 5 dB(A) during the day and 3 dB(A) during the night.
- in the case of a Facility Classified for the Protection of the Environment (FCPE), the marked tone, the presence of which is linked to the difference between the sound pressure level in a given 1/3 octave frequency band and the adjacent frequency bands, is considered undesirable if it exceeds 10 dB in the frequency range 50 Hz-315 Hz or 5 dB in the frequency range 400 Hz-8000 Hz
ITS will contribute to reducing noise from cooling water pumps by installing sound-insulating enclosures at a chemical industry facility in Germany.
For each of the four units in question, the structures will be made of metal, with a footprint of around ten square meters, featuring:
- for fixed or easily removable parts, by elements: industrial soundproofing panels with an absorbing face (modular)
- for acces: (rotating) acoustic doorsets with, for translucent parts (with glazing guaranteeing residual safety in the event of accidental breakage): acoustic window sets
Naturally, the design of such enclosures must take into account site-specific constraints (e.g. access locations, the clearance required for opening sections, and cutouts for piping that must not compromise sound insulation performance) and ensure rapid disassembly and reassembly to facilitate maintenance or repair of the cooling water pumps - components essential for the normal operation of chemical processes, the interruption of which would entail the highly undesirable consequences typically associated with such production shutdowns.
Another major technical aspect of such a project will be the development of the high-performance ventilation system with which each enclosure must be equipped to meet the ambitious target of limiting the temperature rise to less than 5°C i.e. 5 Kelvin (even with such a limit on the temperature rise, the internal environment would still be hot when external temperatures reach or exceed 35°C, a scenario that is far from unusual during summer in temperate regions in the early 21st century: exceeding this limit would affect working conditions for personnel, and certain sensitive electronic components would need to be selected based on even stricter criteria to prevent failure during heat spikes.
Air renewal will require inlets and outlets equipped with ventilation silencers and the installation of fans, inherently noisy themselves, which will demand careful attention regarding selection (e.g. regarding sound emissions) and soundproofing, so as not to compromise the overall effectiveness of the noise-attenuating enclosures.
In such cases, achieving a sound pressure level as low as 62 dB(A) at a distance of 1 meter from the enclosures may seem difficult in practice, if only because background noise (from other noisy equipment at the chemical site, whether nearby or further away) could make verification using a sound level meter challenging. Yet, this is the target set for ITS and its commercial partners by a Client (not the site operator itself, but a world-renowned engineering firm) who knows that, through the project to reduce cooling water pump noise using sound-insulating enclosures, they will obtain equipment that is:
- well-designed (taking into account all constraints inherent to such a project, not just acoustic ones)
- manufactured using premium raw materials and proven welding and assembly techniques
- subject to uncompromising quality control
- delivered on schedule
- highly durable
This is also true of a wide range of noise-reduction equipment across all industrial business sectors, that delights its purchasers and is a source of pride for ITS and its business partners.
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The noise reduction equipment marketed by ITS across all industrial business sectors delights its customers and is a source of our pride. |
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