AIRAH Presentation Case studies in HVAC system noise issues
SLR Consulting Australia Pty Ltd 21 August 2013
Luke Zoontjens
The client / documentation refers to a ‘soundproof’ or VIP space
Use of the prefix ‘acoustic’
Interior services are exposed / open / perforated ceiling
Residential building, or the site immediately borders residences
The site is next to major infrastructure such as rail or freeways
There are scientists, precision equipment, patients, lab animals
Green Star / ESD requirements
Encountered any of the following?
The client / documentation refers to a ‘soundproof’ or VIP space
Use of the prefix ‘acoustic’
Interior services are exposed / open / perforated ceiling
Residential building, or the site immediately borders residences
The site is next to major infrastructure such as rail or freeways
There are scientists, patients or lab animals
Green Star / ESD requirements
Encountered any of the following?
Environmental Acoustics in WA
How big is the consulting industry here?
29+ private firms in Perth alone at last count In no particular order: AECOM, Aurecon, EcoAcoustics, EDC, GED, GHD, HSA, LGA, NDY, SLR, Vipac, ERM, 360Env, MDA, WGE, Precision, SVT/NVMS, Hewshott, WP, Coffey, AI, QuietAcoustics, NDE, URS, Dinglebird, VDM, Instrulabs, Sealhurst, Instrulabs.
• www.acoustics.asn.au • ~600 members nationally, 60 in WA • ‘Learned’ society • Annual conferences and input into
professional standards • Acoustics Australia technical journal
• The peak professional association in the industry; • Up-to-date technology and state of the art practices, Code of
Ethics; • Members work only within their nominated areas of competence
and maintain professional indemnity insurance cover; • Free of commercial activities which may affect their impartiality; • Commitment to undertake regular professional training and
development of all staff.
www.aaac.org.au
DESIGN FRAMEWORKS IN WA
Design Frameworks • State authorities - noise regulations, planning
policies • Local authorities / ‘Sound Attenuation’ policies • Australian standards – comfort, productivity,
fire/life safety, privacy • Industry Guidelines – AIRAH, AAAC etc. • National construction code • Green star / ESD rating tools • Client and user expectations of quality
CASE STUDIES
ADELAIDE
Domestic systems guidance • http://www.fairair.com.au • AIRAH Air Conditioning Residential Best
Practice Guideline (Western Australia) • Installers Guide to Air Conditioner Noise,
RACIRB / Dept Env, Water & Catchment Protection
Section 80 of EPA1986• 80(1) generally states that a person who installs
any equipment which, when operated, emits unreasonable noise commits an offence under the Act.
• The penalty for an offence under Section 80 (1) is $5,000 for an individual or body corporate.
Section 80 of EPA1986• 80(2) generally states that if an occupier is
convicted of committing an offence under the Act because of someone committing offence under 80(1), that occupier may recover the cost of the installation, together with the amount of any penalty imposed on him from the installer by action in court.
Environmental noise limits • Assigned levels for residential buildings under
state noise regulations vary due to ‘influencing factor’, assume LA10 35dB (10pm-7am)
• Note that 5-10dB adjustments are made if the noise has annoyance characteristics (e.g. tonal whine, deterioration over time)
• AIRAH guidelines of LAeq 45dB maximum during the day and LAeq 35dB maximum at night at property boundary – varies between states
1. Distance factor – Assume boundary; within 15m of neighbouring building
2. Barrier factor – 0 if line of sight, 5 or 10 depending on fence – 0 for roof mounted (e.g. evaporative)
3. Reflection factor – 0, 3, 6 depending on surrounding structure – 0 for roof mounted (e.g. evaporative)
Basic approach
57 0 0
Consider roof level installation 10m from boundary
57
45 10 3
Consider ground level installation 2m from 1.8m wall
52
ADELAIDE
AS/NZS 2107 Reception areas target: ~40-45dB(A) Actual: ~61dB(A)
Lessons learnt
• Intake and discharge flow conditions
• Fan unit mounting arrangements
• Lightweight metalwork and panel mode responses
ADELAIDE (again)
Mech Tender
Mech As-Built
AS/NZS 2107 target: ~35-40dB(A)Actual: ~52dB(A)
Lessons learnt
• Beware of areas where the architectural brief calls for perforated metal and feature/exposed ceilings.
• Identify small cellular shared offices and low density workspaces as among the most sensitive.
• Flexible ducting reduces opportunities for future noise control options.
AS/NZS 2107 target: ~30dB(A) State Noise Regulations Assigned
Level: LA10 35dB(A) Actual: LA10 ~44dB(A) Add +5dB for tonality Add +15dB for indoor measurement =64dB(A) … 29dB exceedance
Lessons learnt • Beware of extreme noise control requirements in
residential buildings, particularly those remote from busy roads and commercial areas, and involving mixed uses.
• There is always a physical limit to the performance of noise and vibration treatments; services cannot always be located where it is convenient.
• In a post construction phase of a building, achieving more than a 10-15dB noise reduction via path controls only is excellent.
CLOSING DISCUSSION