A New Alliance
Patching Associates Engineering Ltd. and N.C. Hircock Process Consulting are pleased to announce an extension of their alliance to include Collicutt Hannover Services Ltd. Collicutt Hannover, amongst other services, provide field construction, mechanical repair and mechanical revamps of gas plants and compressors.
In the past, Patching Associates and N.C. Hircock Process Consulting have provided clients with a combination of acoustical and process engineering to provide clients with solutions to either acoustical or plant process problems in such a manner that the operating integrity of the plant is not adversely affected - and sometimes enhanced from both perspectives. This alliance has, in the past, provided conceptual and detailed engineering without necessarily providing the project engineering and mangement necessary to complete implementation of the recommendations.
The inclusion of Collicutt Hannover in this alliance now enables us to provide our clients with full engineering and project services from analysis of the problem to execution of the solution.
Note that this alliance is totally complementary and does not constrain the client to the purchase of process or acoustic related equipment from any one supplier. Acting as independent consultants, R.G. Patching and N.C. Hircock specifically do not have any arrangement or agreement with suppliers of acoustical or process equipment. We are therefore able to independently seek competitive bids from these suppliers to provide the client with the most cost effective solution to acoustic and process problems. The alliance with Collicutt Hannover allows us to provide our mutual clients with a total installed project cost from inceptioin to completion rather than merely quoting FOB shop costs for remedial equipment.
We are sure that this extended alliance will provide our clients with a more complete service. In particular, the client should be able to prepare an AFE for whatever complete installation is required on a given project and thus expedite the approval and completion of these projects.
Noise Impact Assessments
Under the AEUB Noise Control Directive ID 94-4, oil, gas and utility operators are required to conduct a Noise Impact Assessment prior to the installation of new or modsified facilities. While this is often not much of a problem in remote areas, this can create potential difficulties in moderately populated rural areas. If there are any residences within approximately 1000 metres of a single gas compressor or approximately 1500 metres of a small/medium gas processing plant, then a Noise Impact Assessment will usually indicate that some degree of extra noise control may be necessary to meet the Directive. In any event, even in remote areas, the facility should be designed not to exceed 40 dBA at 1500 metres.
Noise control included at the design stage of a new or modified facility, will usually add no more than 0.5 to 2.5% to project cost - depending upon the size of the facility and the proximity of the nearest resident. Noise control considered as a retrofit after complaints arise will usually cost two to four times (or more) as much as the same control included with the original design.
In predicting noise levels, operators can often work successfully with silencer suppliers to predict engine exhaust noise with some accuracy. However many operators have difficulty accurately assessing fan noise and engine casing noise. Cooler fans and engine casings are often incorrectly assumed to be point noise sources. This leads to under-estimation of the total noise emissions. Many styles of cooler fans are also highly directional with regard to noise propagation. This effect is sometimes misunderstood with the result that cooler fan orientation is sometimes not optimized at the design stage.
Engine casing noise is often ignored altogether. Building attenuation is often over-estimated resulting in optimistic environmental assessments. In practice, the building attenuation is limited by the open area required for ventilation, which is often inadequate for the task.
This is proven by the need to leave the building doors open in summer to prevent overheating. The open doors, of course, eliminate most of the noise control offerred by the building. The design of compressor buildings and ventilation systems to suppress and minimize the effect of engine casing radiated noise is relatively simple at the design stage and more complicated with field retrofits.
Patching Associates handle some 100+ oil, gas and utility noise control projects annually. Approximately half of these tend to be the more expensive retrofits rather than initial design considerations. We would like to remind our clients that we are available to work with your project or contracting engineer at the design phase in order to eliminate the need for potentially costly retrofits once the facilities are commissioned and subject to potential resident complaints.
