Nois-eNvelope Case Studies

Problem:

A global chemical manufacturing plant struggled to meet the health and safety noise requirements imposed by the ministry of environment caused by excessively loud rooftop industrial fans. Although the chemical plant is located in an industrial area, complaints from a residential area located on the outskirts were made to the regulatory agency responsible.

To achieve a more comfortable noise level, for both workers in the plant and the residents of the surrounding areas, an acoustical consultant was commissioned to determine the most appropriate action. It was determined that a three sided acoustic enclosure for the industrial rooftop fans would solve the noise issues and allow them to be compliant with regional noise regulations.

Challenges:

Once a course of action was determined by the acoustics study, dB Noise Reduction^® was contacted to engineer, manufacture, and supply the noise enclosures. With the magnitude of the job, a structural engineer was consulted to examine the existing structure of the roof. It was determined with the additional weight load of the new equipment, the existing roof structure was in need of reinforcement.

There are very strict health and safety policies when working construction and installation at a chemical manufacturing plant. The ability to cut, weld, and grind is very limited adding to the complexity and challenge of this job.

Solution:

One of the many benefits of dB Noise Reduction^® is their ability to take a project at the very beginning and while working with different agencies, see the project through to completion and customer satisfaction.

There are typically three types of noise associated with industrial fans: noise generated by the airflow, noise generated through the casing (fan housing and ducts), and noise generated by the motor & shaft that drive the fan. Noise enclosures are the best solution when it comes to reducing all three types of noise at once, therefore this was the method used to attenuate the fans.

Nois-eNvelope™, a product line of dB Noise Reduction^® that involves engineered acoustic noise panel and barrier systems, was the perfect fit for this job. Using the report submitted by the acoustical engineer and local noise regulations for the requirements, a three sided acoustic enclosure was designed to enclose the fans. The job was very complex, posing many challenges and required a unique design. dB Noise Reduction^® working along-side the structural engineer and other agencies were able to come up with an effective solution to a common noise problem, challenged by the scope of the job and the type of manufacturing plant the fans were located in.

From the original requirements specified by the acoustical consultant (See Table 1); Nois-eNvelope™ noise barrier system met and exceeded the required noise reduction (See Table 2). This alleviated the invasive noise that affected the nearby residents.

Table 1: Acoustical Consultant's minimum Noise Control Enclosure Transmission Loss (TL) requirements:

Octave Ctr Frequency (Hz)	63	125	250	500	1000	2000	4000	8000
Transmission Loss (TL)	7	9	12	14	10	9	6	0

Table 2: Nois-eNvelope™ A4L Panel Transmission Loss (TL) performance:

Octave Ctr Frequency (Hz)	63	125	250	500	1000	2000	4000	8000
Transmission Loss (TL)	11	20	26	41	53	56	62	60