NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Noise Control for Portable Ventilation Blowers January 2014 - December 2014 Daniel O. Chute, CIH, CSP Atrium Environmental Health and Safety Services - Reston, VA 1 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 2 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Research Team Dan Chute from Atrium Steve Szulecki, The Noise Consultancy HI – Newport News (David Baize) EB – Electric Boat (Stacy Herritt) 3 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Concept Description Portable Ventilation Blowers (PVB) used in shipboard construction and repair present many noise control challenges. In addition to the noise generated by motors, fans and air movement, noise control in this work environment is complicated by noise and vibration-conductive mounting surfaces on metal hulls and deck plates, equipment that is mobile with possible relocation on a daily or weekly basis, rugged handling and maintenance. Previous work at shipyards and through NSRP has demonstrated these PVBs to be a major contributor to shipboard noise levels during construction and overhaul. Experience, observation and testing has suggested that several practical control options such as vibration isolators, acoustical jackets, duct silencers and enclosure partitions have the potential to offer feasible noise reduction solutions. No published studies or reports are available however to demonstrate how these noise control strategies may be achieved in the shipbuilding industry. 4 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Project Goals and Objectives 1. Take a systematic and methodical approach to determine what practical measures may be applied to offer effective noise reduction in the use of PVB, 2. Prepare and apply a variety of selected noise control treatments on the primary PVB model used at each participating shipyard, 3. Conduct follow up testing to measure the effective noise reduction from these treatments, and 4. Deliver a written report to define the methods, cost, application and noise reduction benefits of the selected treatments. 5 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Milestones 1. Complete Background Research and Develop Field Testing Plan 2/28/14 Completed 1. Field Testing and Analysis 5/30/14 Completed 2. Application and Testing of Selected Noise Reduction Treatments 8/30/14 In Progress 3. Prepare Draft Report 10/30/14 --------------- 5. Deliver Final Report 12/30/14 --------------- 6 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Historical Data • Navy NOED Database • Navy Safety Center • NSRP Studies and Technical Reports • Industrial Hygiene Literature • OSHA and NIOSH Studies 7 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Previous Noise Reduction Strategies 8 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Previous Noise Reduction Strategies 9 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Previous Noise Reduction Strategies 10 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Previous Noise Reduction Strategies 11 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Previous Noise Reduction Strategies 12 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Field Testing Plan • • Visits to HII-Newport News and Electric Boat to evaluate noise from selected representative shipboard PVB units under simulated conditions of current use. Baseline data will allow the project team an opportunity to observe and evaluate several factors which may contribute to the noise generated by this equipment and, in turn, provide modification options for effective noise reduction strategies including: Model and size of blowers in use; · Positioning and mounting; · Manifolds and ducting; · Maintenance and repair procedures; · Other adjacent noise sources; and, · Reverberant surfaces. - 13 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 • The sound pressure levels will be measured and sound power levels calculated based on ANSI/ASA S12.54-2011 / ISO 3744:2010, Acoustics – Determination of sound power levels and sound energy levels of noise sources using sound pressure – Engineering method for an essentially free field over a reflecting surface. 14 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 • Photographs will also be taken of the tested PVB under representative conditions of use. These photographs will be subject to the required security clearance review and “sanitized” as needed for use in subsequent written reports. 15 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Noise Control Options May Include: • • • • • • • Mounting dampers, pads, seals, vibration isolators; Padded or insulated enclosures; Different fan sizes or composition; Changes to manifolds and ductwork to reduce conductive noise; Maintenance and lubrication procedures; Positioning of directional noise sources; Minimizing proximity or reverberation from adjacent conductive surfaces; and, • Discharge baffles or silencers (mufflers). Discussion with Blower Manufacturers to test and apply proven solutions. 16 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Site Visits for Testing • HI – Newport News, Newport, Virginia on March 17–19, 2014 PVB = 10 HP Robinson Blower • General Dynamics Electric Boat, Groton, CT on April 7-9, 2014 PVB = Coppus, Inc. TM-8 (15 HP) unit 17 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Baseline (pre-abatement) Third-octave and Broadband Sound Power Levels for the Selected PVB at NNS and EB. The TM-8 PVB in-use at EB are equipped with a dissipative-type silencer which is installed at the outlet of the unit. Pre-abatement, baseline sound level measurements were conducted with and without the silencer installed to assess the effectiveness of the silencer. 18 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Proposed Noise Reduction Treatments for Follow Up Testing Robinson Blower • Outlet silencer (dissipative style) to be tested on the outlet flange of the PVB. A dissipative silencer is designed to have a minimal pressure drop and, as such, the effect on the flow rate is also minimal. A large percentage of the PVB in-use at NNS are located within interior spaces of ships which are under construction or renovation. Many of these PVB exhaust directly into these interior spaces. The noise emitted at the exhaust is one of the primary contributors to the overall noise emissions from the PVB. The use of a silencer in this application will reasonably reduce the sound emission levels from the PVB. • Vibration-isolation mounts to be installed for testing on the four corners of the lower frame of the PVB to interrupt the path that current allows vibrational energy of the PVB to be transferred to the deck of the ship. PVB as currently configured with wheels, in contact with the ship deck, that are non-resilient. The vibration-isolation mounts will be a “housed spring” type of mount that is durable and effective. A neoprene pad is adhered to the base of the mount. A spring type mount is effective at reducing low- and midfrequency vibration; while a neoprene pad is effective for high-frequency vibration. • Acoustical “jacket” to be installed around the fan housing to increase the insertion loss of fan housing and thereby reduce the sound emission levels from this portion of the 19 PVB. NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Proposed Noise Reduction Treatments for Follow Up Testing Coppus Blower • Inlet silencer (dissipative type) to be tested on the inlet flange, of a multi-inlet adapter, that is typically left “open” (no duct attached). A dissipative silencer is designed to have a minimal pressure drop and, as such, the effect on the volumetric flow rate is also expected to be minimal. The use of a silencer in this application will reduce the sound emission levels from the PVB since the “open” inlet represents the largest contributor of noise associated with PVB. Alternatively, a short length of flexible duct attached to the “open” inlet will also be tested and compared to the data for the “open” inlet silencer. This may provide for a low cost solution that is reasonably effective. • Acoustical curtain – to interrupt the direct sound path between the location of the PVB and the position of the “tanker watcher.” In addition to serving as a barrier to the direct sound path it will also serve to absorb sound that would otherwise reverberate within the acoustically “hard” surfaces found in the boat basin. • Acoustical “jacket” to be installed around the fan housing to increase the insertion loss of fan housing and thereby reduce the sound emission levels from this portion of the PVB. 20 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Exhaust Air Discharge 21 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 New PVB Unit Awaiting Evaluation 22 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Weight Measurement on Scale 23 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Shipboard PVB System In Use 24 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Top View, PVB Units in Drydock 25 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 PVB Unit with Discharge Silencer Removed 26 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Examination of Silencer Baffle System 27 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Sound Measurement at Exhaust Discharge 28 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 29 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 30 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 31 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 32 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 33 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Sound Seal's Industrial Sound Curtain composites offer maximum noise reduction on any application by combining sound absorption and noise barrier materials. Industrial Sound Curtains are available in a barrier backed or barrier septum configuration utilizing a variety of quilted fiberglass absorbers and flexible noise barriers. Barricade sound absorption/noise barrier sound curtains are supplied as roll goods, enclosure systems, acoustical jackets and die cut pieces. • • • • • Excellent Soundproofing performance STC ratings up to 32 NRC ratings up to 1.05 Class A flammability ratings Flexible composites conform to any shape 34 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 35 NSRP RISK MANAGEMENT PANEL PROJECT, 2014-424 Questions?? 36
© Copyright 2024 ExpyDoc
