HOTCHKISS AIR ACOUSTICS

Transcription

1 HOTCHKISS AIR ACOUSTICS S o u n d P A C P r o d u c t s

2 noise problems in ducts the straightforward solution Fan noise In systems utilising a local small fan or even in larger installations with remote fans and primary sound attenuators, residual airborne fan noise may be unacceptable. Install SoundPAC inserts at terminal conditions. System regenerative noise Integrating mechanical services into any building always calls for compromise. Frequently, tortuous duct paths or pressure regulation at branch volume control dampers result in high levels of regenerative noise, the practical effect of which is unacceptable noise levels at grille outlets. Install SoundPAC inserts at system outlets. Fan coil units Fan coil units mounted in the ceiling void are a common method of providing economic and responsive heating/cooling locally to the spaces served. However, their proximity to the conditioned area means that their inherent noise becomes prominent in many instances. Often units are oversized to compensate for this problem. Sound attenuation is frequently required on the discharge side and, in some cases, on the intake side as well. Install SoundPAC inserts in the fan coil unit discharge and/or intake ductwork. Ductwork system cross-talk Where adjacent rooms share a ductwork system, the sound insulation value of the dividing wall can be significantly compromised by this path. This is a situation which frequently occurs in offices. For example, a blockwork wall offering a Sound Insulation value of 41dB would be reduced to 25dB by a 200 x 200mm interconnecting duct, considerably affecting the privacy enjoyed by those rooms. Install SoundPAC inserts in the terminal ductwork to each room.

3 Design SoundPAC the material SoundPAC is made from an open-cell melamine resin foam. It is: sound absorbent flexible dimensionally stable non-fibrous surface spread of flame to Class O easy to cut Performance An extensive range of SoundPAC inserts have been tested both singly and in a variety of configurations generally to BS Resistance to airflow was determined using CIBSE prediction methods assuming ductwork designed in accordance with current good practice and verified by practical measurement. Pressure loss against duct velocity In accordance with the CDM Regulations, full details of the material are available on request. SoundPAC the product SoundPAC is produced in 2 basic forms: SoundPAC CDI for circular ducts The CDI inserts are installed singly. Being accurately made and resilient the inserts are designed for a compressive fit and normally remain in their installed position without the need for additional fixings. At normal working terminal air velocities, SoundPAC causes minimal additional system pressure loss. SoundPAC sound insertion losses SoundPAC RDI for rectangular ducts The RDI inserts are designed to be installed either singly or in multiples depending upon the duct size. A self-adhesive film on the base of the insert helps to hold it in place in the duct. Further advice To a specific ductwork noise problem there could be several SoundPAC solutions. Hotchkiss s Technical Support Department is able to offer design advice on a project basis. Application sheets for common problems are available upon request. Measured average insertion loss for CDI and RDI inserts at 600mm and 1200mm lengths for the common range of duct sizes. 90 Octave band sound pressure level db re 2 x 10-5 N/m NR60 NR55 NR50 NR45 NR40 NR35 NR30 NR k 2k 4k Octave band mid frequency hz For the room arrangement shown above a noise rating of NR35 might reasonably be selected as a design criteria to provide a satisfactory working environment. The red curve shows a typical in-room sound spectrum associated with noise regeneration at the volume control damper. The yellow curve above illustrates the noise criteria achieved by the 600mm long SoundPAC inserts within the system ductwork.

4 Availability Standard range inserts are readily available from stock using the Ordering Codes given below. Non-standard sizes are available upon request. Standard Range SoundPAC CDI for circular ducts Notes 1) CDI inserts are installed singly. 2)* Inserts can be ordered in 2 lengths: 600mm Ordering Code.../L6 1200mm Ordering Code.../L12 Inserts can be readily cut to any required intermediate length. Also, multiple inserts can be fitted to achieve any overall length in excess of the standard sizes. Ordering Codes related to common duct sizes SoundPAC RDI for rectangular ducts Notes 1) Depending on the duct size RDI inserts are installed as single units or in multiples as required. See examples below. 2)* Inserts can be ordered in 2 lengths: 600mm Ordering Code.../L6 1200mm Ordering Code.../L12 3) Typical arrangements for 600mm long inserts. Duct size Insert Ordering code W H W 200x200 RDI R2020/L6 H 300x200 RDI 2No.R1520/L6 H Duct dia CDI Ordering Code D 100 C10/L* 125 C12/L* 150 C15/L* 160 C16/L* 180 C18/L* 200 C20/L* 224 C22/L* 250 C25/L* 280 C28/L* 300 C30/L* 315 C31/L* 355 C35/L* 400 C40/L* 450 C45/L* Ordering Codes related to common duct sizes Duct size RDI Ordering Code W x H 100x100 R1010/L* 100x150 R1015/L* 100x200 R1020/L* 100x250 R1025/L* 100x300 R1030/L* 100x400 R1040/L* 150x150 R1515/L* 150x200 R1520/L* 150x250 R1525/L* 150x300 R1530/L* 200x200 R2020/L* 200x250 R2025/L* 200x300 R2030/L* 200x400 R2040/L* 250x250 R2525/L* 300x300 R3030/L*

5 What is SoundPAC? SoundPAC is a new, innovative product (patent pending) for the control of noise associated with heating, ventilating and air-conditioning ductwork. The SoundPAC concept provides the optimum combination of acoustic material and section profile for enhanced attentuative performance at cost levels well below those associated with traditional products/techniques. It offers the ideal practical solution to many problems. For both new-build and refurbishment Being inherently flexible the inserts are particularly suited to retro-fit installation where restricted access and/or minimal disruption is a consideration. The low cost for the installation of the product allows designers the advantage to specify SoundPAC as a precautionary noise-control safeguard. Such a pre-emptive approach simplifies acoustic design considerations in respect of the inevitable oversights and compromises encountered during system installation. Designed to satisfy Health and Safety legislation The general concern about building-related illnesses, ranging from chronic discomfort to acute ailments - the Sick Building Syndrome - is now embodied in legislation. The approved code of practice to The Workplace (Health, Safety and Welfare) Regulations 1992 states that ventilation systems should be properly cleaned, tested and maintained to ensure that they are kept free of anything which might contaminate the air. Those responsible for managing properties are now beginning to realise that the only way to satisfy the Environmental Health Officer or the Health and Safety Inspector is to carry out these maintenance procedures to a regular programme. SoundPAC has been developed to contribute to this increasingly important good housekeeping process: its cost is such that inserts can be replaced in the course of future maintenance rather than cleaned its white colour enables the degree of contamination to be easily checked during inspections its non-fibrous nature eliminates any risk of fibre migration it works in conjunction with new methods of duct cleaning which allow ductwork to be retained and upgraded in refurbishment projects rather than entirely renewed its specification instead of more complicated forms of sound attenuators saves on both initial installation and future cleaning costs Competitively priced and easy to install makes SoundPAC the most economic solution to all ductwork noise problems. SoundPAC is readily available in different sizes to suit all standard rectangular and circular ductwork sections. Being flexible it can be fitted even in the most constricted of locations. Routine inspection and cleaning of ductwork is essential in any well managed property. A range of contaminants can accumulate in supply and re-circulation systems. - carbonaceous and crystaline particulates, skin flake, paper dust and textile fibres, degraded insect and vegetable matter, corrosion products and man-made mineral fibres - and where dirt accumulates, micro organisms such as bacteria, fungi and yeast can thrive. To these potential health hazards can be added increased fire risk and decreased system efficiency. A properly cleaned duct Photograph courtesy of System Hygenics Ltd

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