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Buy Quiet Noise Purchasing Policies, Standards and Training

Buy Quiet – effective specifications

Don’t let your suppliers waste your money on noise control measures that are not best practice…

Implementing and policing a noise buying policy for new plant can be either the single most cost effective – or one of the most expensive – long term noise reduction measures that a company can take.

The difference lies in the way that the noise buying policy is implemented. As most suppliers have little or no noise control expertise, they often purchase off-the-shelf acoustic enclosures, silencers and materials which they then mark-up and sell-on instead of using best practice. Suppliers have been known to continue selling noise enclosures when they know there are cheaper and more effective engineering alternatives simply because they are more profitable…

Get a copy of the Buy Quiet technical note

If you simply lay a Buy Quiet noise specification suppliers, they will often just buy-in palliative measures. In effect, you’ve given them a licence to spend your money on noise control measures that are not best practice. This can be expensive…

Cost Savings
In a surprising proportion of cases, implementing current best practice noise control technology will reduce noise levels below that at which PPE is required. As claims evidence (c £400 million in UK in 2014) and HSE research proves that PPE is ineffective as currently used, effective noise control can reduce costs dramatically.

The INVC template Buy Quiet purchasing policy is the basis for a practical and easily policed procedure.  Based on operational experience, it has been demonstrably highly effective across a wide range of industries.

Buy Quiet Occupational Purchasing Policy – Caveat Emptor

Once you have installed new plant that generates high noise levels, it becomes your responsibility to reduce noise levels as far as reasonably practicable.  This can be a high cost process as each company independently re-invents the “noise control wheel”. Moreover, the decision to purchase may have been based on competitive prices that did not include allowances for noise control. The best way to minimise the full costs of purchasing new plant and complying with the regulations is to implement a Buy Quiet purchasing policy and order to a Noise Buying Procedure.  Not only does this reduce the chance of importing fresh noise problems, but it also puts pressure on suppliers to reduce noise at source and to meet their duties under the legislation.

This vibratory grader generating 99dB(A) was picked-up prior to delivery by a company using our noise buying policy. The supplier suggested additional screens and guards at high cost and with no guaranteed noise level. Our diagnostic tests during proving trials led to the company purchasing the line subject to installing our recommended engineering noise control measures. These not only reduced the noise to 85dB(A) at a cost of a few £00’s (as against the several £000’s plus access and hygiene issues) previously considered, but they could also have dispensed with the existing enclosure – saving an additional £25k.

Noise control measures must be justified by evidence based on source diagnosis and ranking. If this information is not available, then the noise reduction techniques are based on guesswork and are highly unlikely to constitute best practice with implications re cost and productivity. If the supplier does not have the necessary expertise, then an expert engineering evaluation of the options must be made (a regular for us) and the plant purchased subject to implementing agreed best practice noise control measures.

Get a copy of the Buy Quiet technical note

Contact us for a copy of the technical note or to discuss Buy Quiet noise purchasing policy template, technical support options or Buy Quiet noise specification training.

Buy Quiet Environmental – IPPC Management

The Buy Quiet template specifications and procedures ensure you meet your IPPC Licence and ISO14001 noise specifications and requirements for the future as cost effectively as possible. The procedure includes template documentation (in digital form – with sound samples) and procedures for inclusion in company policy covering new plant and site changes. It can also be extended to include a detailed environmental noise control and management programme to minimise future costs.

Past experience with the effectiveness and cost savings realised by our noise control recommendations led CMB, for example, to include a recommendation that engineers get our evaluation of the options in all projects where environmental noise is an issue.

Buy Quiet in Action – Case Studies

Tobacco Industry Making Machinesmolins cigarette making machine noise reduction package as part of the buy quiet policy

Effective Specification
A very simple noise limit of 85 dB(A) at 1m was specified by the purchaser. The supplier’s interpretation included averaging noise levels all round the machine and applying an (unjustifiable) room correction factor to give a figure of 84.8 dB(A) (!). The operator noise level measured in the factory was an unacceptable 90 dB(A). This highlights the necessity for a purchasing specification that does not leave contractual loopholes.

Reduced Control Costs
The same supplier also provided 3 machines, each sporting c£5000 of noise control modifications to meet 85 dB(A) (purchase of a further 12 machines was planned). We developed simple retro-fit engineering noise control modifications costing c £400/machine that gave a similar performance to the manufacturer’s measures – a cost saving of c £40k.

Supplier Benefits
The rights to an INVC developed low cost retro-fit engineering noise control kit for a Molins cigarette making machine were purchased by the manufacturer. As it eliminated the requirement for mandatory PPE, it proved very popular and was sold world-wide to existing customers as a highly profitable product in its own right.

Machine Tools – Multi-Spindle Lathes
The purchaser of several multi-spindle auto lathes was on the point of cancelling the order as the first completed machines did not meet the agreed noise level of 83 dB(A) (3000 rpm) – they were typically generating 87 – 90 dB(A). We used the results of sophisticated noise and vibration analysis to recommend a change in the assembly procedures used that reduced noise levels to 83dB(A) at negligible cost. The diagnosis and recommendations were completed in less than 2 days and, as a result, all purchasers now receive quiet machines. This illustrates the benefits of effective policing of purchasing requirements.

CompAir Compressorscompair air compressor noise reduction as part of buy quiet policy
As part of a continuous product development programme and pressure from customers to reduce noise levels, CompAir asked us whether it would be feasible to improve the noise control package on one of their compressors.

Source control modifications were developed for the cooling system which reduced the overall noise from this element and also cut the tonal content (less “nuisance”). Coupled with modest flow and geometry changes, the new package reduced the overall noise from the compressor by 2 – 3dB(A), despite removing the standard silencer (which reduced the size of the machine) – and all without any cost or performance implications.compair before after


Hosiery Manufacturing Machines – Detexomat Speedomatic

detexomat hosiery machine noise reduction as part of buy quiet standardA major customer implemented our Buy Quiet purchasing policy and passed-on to the supplier a request to reduce the operator noise levels from 90dB(A) down to below 85dB(A) in the production environment. We were retained by the manufacturer to provide design improvements as part of the of the machine development programme. Our engineering recommendations reduced the machine noise down to 82dB(A) at a cost of around £300 per machine (c 2% of the capital cost) without affecting normal operation or access. Modifications included sewing machine damping, control of exhaust air and minor changes to the machine base.

Vibratory Sieves and Separators

vibratory sieve noise control using dampingspun component for low noise vibratory sieveAs product noise levels were becoming an increasingly important factor for their clients, the manufacturer came to us for advice – the conventional wisdom was to use enclosures and screens which had an impact on access and hygiene. We developed some novel engineering modifications and proved a new material/manufacturing process that reduce the noise from the sieves at source by 5dB(A) at an additional cost of only £200 per machine.

Weighing Machines – hygiene requirements for confectionery

reducing the noise from weighing machines for high hygiene confectionery as part of buy quiet standardWeighing machines for the confectionery industry are a common noise problem. In this case, the purchaser had implemented our Buy Quiet policy for new plant, with a target of 75dB(A) for this particular installation. One of our engineers attended the proving trials at Easiweigh. We developed a set of modifications that reduced the initial 83dB(A) Leq noise level down to the required 75dB(A) Leq . The low cost, high hygiene modifications included replacing the conventional damping with high performance stainless constrained layer damping. This has since been adopted as standard practice.