Environmental Noise Survey - Final Report

Tullow Ghana Ltd Onshore Environmental Noise Monitoring [Survey Report] July 2012 By: Emmanuel Arthur Environmental Advisor EHS Department 1|Page Environmental Noise Survey Conducted by: 1. Emmanuel Arthur Environmental Advisor EHS Department Accra 2. Frank Awuah-Antwi GIS Advisor EHS Department Accra 2|Page Table of Contents 1.0 Introduction ..................................................................................................................... 4 1.1 Noise Terminology and Definitions ............................................................................................... 4 2.0 Noise Survey Scope and Methodology ............................................................................... 5 2.1 Noise Measurement Mode - Free Field .................................................................................. 5 2.2 Sound Level Meter Field Deployment..................................................................................... 5 2.3 Duration/Averaging time ........................................................................................................ 5 2.4 Selected Octave weighting...................................................................................................... 5 2.5 Noise level time history data logging mode ........................................................................... 5 3.0 Noise Measuring Equipment – Sound Level Meter (SLM) .................................................... 7 4.0 Noise Survey Data Analysis and Reporting ......................................................................... 9 4.1 Typical noise source decibel comparison chart .......................................................................... 10 5.0 Results and Analysis ........................................................................................................ 11 5.1 Survey Operations Summary ................................................................................................ 11 5.2 Weather Conditions .............................................................................................................. 11 5.3 Main Survey Runs.................................................................................................................. 11 5.4 Noise Data Analysis ............................................................................................................... 12 5.5 Potential Impacts of environmental noise exposure ............................................................ 16 5.6 Noise Control measures ........................................................................................................ 16 5.7 Investigative Run ................................................................................................................... 16 6.0 Conclusions and Recommendations................................................................................. 17 Appendices ................................................................................................................................ 18 Appendix A: Location maps showing measurement positions for the various sites ........................ 18 Appendix B: Noise level time history logs taken at the various measurement positions ................ 22 3|Page 1.0 Introduction The assessment of environmental noise within an operational area or industrial workplace typically requires that you capture an uninterrupted history of noise data for a temporary but extended period of time. Environmental noise measurements within Tullow operational areas are one of the environmental parameters within the TGL monitoring plan that has to be monitored. Environmental noise survey is necessary to assess noise baseline conditions within operational areas and to ascertain if noise levels emanating from operations has any detrimental impact to the local environment or has potential to cause nuisance at noise sensitive locations e.g. schools, health facilities or residential communities. The survey is planned to be conducted within Q3 and Q4 of 2012. Each survey period would last a week. The survey will investigate the following: 1. The probability of noise emissions causing annoyance and/or disturbance 2. The nature and character of the locality and the background noise 3. The characteristics of the noise sources at operational sites – e.g., is the noise typically broad-band, tonal and/or impulsive. 4. The normal operating times of noise sources at operational sites and any possible variations or irregular emissions, e.g., intermittent emissions. 5. Operational noise levels in comparison to EPA ambient noise limits 1.1 Noise Terminology and Definitions Decibel (dB): The standard unit for measuring sound pressure level and noise exposure. dB(A): A-weighted sound level in decibels. SPL: The sound pressure level. This is the basic physical measure of noise and is normally expressed in dB. LAeq: This is a general descriptor of environmental sound exposure. It the equivalent continuous sound pressure level. It is an average of the total sound energy measured over a specified period of time. It represents the level of a steady, continuous noise that has the same total energy as the real varying noise measured over the same period. LAmax: The maximum RMS, A-Weighted sound pressure level occurring within a specified time period. LAmin: The minimum RMS, A-Weighted sound pressure level occurring within a specified time period. Threshold: The sound pressure level below which sound measurements are excluded from the calculation. 4|Page Statistical values The statistical functions L10, L50 and L90 show the sound pressure levels that are exceeded for 10 %, 50 % and 90 % of the measurement period respectively. L10 therefore is the measurement exceeded for 10 % of the measurement time and L90 is the level exceeded for 90 % of the measurement time. 2.0 Noise Survey Scope and Methodology The scope and the extent of the noise survey is intended to reflect the site-specific conditions of each site in respect of noise generating sources and activities. 2.1 Noise Measurement Mode - Free Field Class I Sound level meter (SLM) in free field measurement mode would be used for the noise survey. These are conditions in which the waves from sound sources is unaffected by the presence of any reflecting boundaries. In environmental noise, true free-field measurement conditions are achieved by positioning microphone at a height between 1.2m and 1.5m above ground level. SLM in free field measurement mode would enable background noise level measurements at all locations. To minimise the influence of reflections, instrument position would be at least 3.5 metres from any reflecting surface other than the ground. 2.2 Sound Level Meter Field Deployment Noise monitoring equipment would be set up in all locations as indicated in the survey map (see figure 1). Generally, the sound level meter deployment in the field would not have the full weatherproof windshield cover installed over microphone. However where there are clear and present hazards to equipment deployed, microphones would be fitted with weatherproof windshield and calibrated before and after survey to ensure a consistent and acceptable level of accuracy was maintained. If weather conditions are harsh and unfavourable, measurements would be suspended and rescheduled to a later date. 2.3 Duration/Averaging time 9 Hr unattended daytime noise measurement would be undertaken on each site. Automatic unattended logging of noise levels is appropriate for this survey since no doubts exist about the noise sources at the various operational sites. Attended measurements would be conducted where necessary in a follow up survey if certain patterns or peaks cannot be logically explained. Attended measurements will facilitate the identification of any extraneous sources, tonal elements and for additional noise source information. 2.4 Selected Octave weighting The A octave weighting filter would be used for the environmental noise measurement. The A weighting is the usual method of adjusting the measured sound pressure level so that the measurements represent the frequency response of the human ear. 2.5 Noise level time history data logging mode Cumulative: A single profile recording/data logging consisting of a series of fast measurements made at the same time as a cumulative measurement (08:00 – 17:00 duration). 5|Page Table 1: Tullow Operational Sites and Description Survey Sites Site Description Main Noise Sources Survey date 1. Shore base Pipe yard Tubulars/Casing, drill strings and other offshore well hardware stored on site. Lifting operations by cranes conducted on site. Site is close to Takoradi Airport runway. Aircraft Noise (fixed winged and helicopter flights) Traffic Noise from trucks Gun fires Crane operations Tuesday 2. Shore base Office Logistics Base Office Tuesday Proximity to Takoradi heliport (approximately 150 m) Traffic noise Aircraft noise (fixed wing and helicopter flights), Crane operations Gun fires 3. Takoradi Port – FPSO Chemical Facility Chemical decanting facility existing within the Takoradi port. Port operations (i.e. vehicular traffic, crane operations, Wednesday 3rd July 2012 3rd July 2012 4th July 2012 Quayside, sea background noise from wave and current actions 4. Airport Ridge staff house Residential facility selected for reference purposes Human habitation community background noise Thursday 5th July 2012 6|Page Figure 1: Map of operational sites showing the locations of the measurement positions 3.0 Noise Measuring Equipment – Sound Level Meter (SLM) The sound level meters to be used for the survey is the Casella 63x series Class I Model. Tabulated below are the relevant details on the equipment. Table 2: Casella 63x Equipment Details Equipment Manufacturer Model Type Sound Level Meter Casella Sound Level Meter Casella CEL 63 x Serial Number Calibrator 3411173 CEL-110/1 Class I - (CEL251) 50 mV/Pa sensitivity 0 – 140 CEL-110/1 Class I - (CEL251) 50 mV/Pa sensitivity 0 – 140 3411172 Firmware version 129.02 Thresholds dB Firmware version 129.02 CEL 63 x Microphone 7|Page A pictorial image of the SLM and calibration screen shots is as shown in figure 2. Figure 2: SLM with screen shots of its calibration Figure 3: A pictorial of outdoor deployment/ installation of sound level meter 8|Page Casella 63 x series SLM Standards The CEL-63x instrument provides Sound Pressure Level (SPL), Integrating and Octave band noise measurements compliant with the following international standards: • IEC 61672-1: 2002-5 (Electro-Acoustics – Sound Level Meters) Group „X‟ instruments. Performance of Class 1 or 2 as relevant to the instrument model. • • 4.0 IEC 60651: 1979, IEC 60804: 2000, ANSI S1.4 1983, ANSI S1.43-1997(R2007) 1/1 Octave and 1/3 Octave Filters comply with EN61260: 1996, Class 0 and ANSI S1.11 1986, Order-3 Type 0C. Noise Survey Data Analysis and Reporting After the survey, results of the unattended noise measurements at all locations would be downloaded unto a field laptop with the instrument data analysis software for graphical display of noise level time history – Casella Insight. The Casella Insight data management software is used to combine and graph noise periodic data logged. Data can be viewed in tabular or graphical format and analysed as necessary. The Insight software includes analysis and graphing tools, which can be used to analyse and view measurement runs. Measurements taken at all locations would be incorporated onto a GIS platform (ARCGIS 10) and shown in a map. The noise survey report will include a statement on compliance with respect to noise levels at operational sites in relation to EPA ambient noise limits for industrial areas. Table 3: Noise Survey Results Format Measurement Position Period 1 Shore base Pipe yard 0800 – 17:00 2 Shore base Office 0800 – 17:00 3 Takoradi Port – FPSO Chemical Facility 0800 – 17:00 4 Residential reference – Airport Ridge staff house 0800 – 17:00 LAeq LAmin LAmax L10 L90 9|Page Table 4: EPA Ambient noise limits according to zones ZONE A DESCRIPTION OF AREA OF NOISE RECEPTION PERMISSIBLE NOISE LEVEL IN dB(A)/LAeq DAY TIME NIGHT 0600 - 2200 2200 - 0600 Residential areas with low or infrequent transportation Educational (school) and health (hospital, clinic) facilities Areas with some commercial or light industry 55 48 55 50 60 55 65 60 C2 Areas with some light industry, places of entertainment or public assembly, and places of worship located in this zone Predominantly commercial areas 75 65 D Light industrial areas 70 60 E Predominantly heavy industrial areas 70 70 B1 B2 C1 4.1 Typical noise source decibel comparison chart To give a sense check on sound levels here is a compilation of decibel levels measured for a variety of noise sources, that help one to understand the volume levels of various sources and how they can affect our hearing (see table 5). Table 5: Typical noise levels recorded for various noise sources Sound Sources (Noise) Sound Pressure Examples with distance Level Lp dB SPL Jet aircraft, 50 m away 140 Threshold of pain 130 Threshold of discomfort 120 Chainsaw, 1 m distance 110 Disco, 1 m from speaker 100 Diesel truck, 10 m away 90 Kerbside of busy road, 5 m 80 Vacuum cleaner, distance 1 m 70 Conversational speech, 1 m 60 Average home 50 Quiet library 40 Quiet bedroom at night 30 Background in TV studio 20 Rustling leaves in the distance 10 Threshold of hearing 0 10 | P a g e 5.0 Results and Analysis 5.1 Survey Operations Summary The onshore environmental noise survey was conducted as planned. The report provides details of the noise survey conducted 3 -6 July 2012 and sets out the results and its analysis. A noise survey consisting of attended and unattended parts has been conducted on site. Initial trial runs were conducted to function- test the equipment in field deployment. 3 hr duration runs were conducted at two of the predetermined sampling locations and the results of the runs are as shown in the table below. Table 6: 3-hr duration trial runs of noise meters and results Survey Sites Type of Run Start Time End Time Duration LAeq L10 L90 Lmin Lmax Shore base Pipe yard Trial 14:00 17:00 3 hrs 70.4 75.5 62.5 46.4 91.1 14:00 17:00 3hrs 68.2 71.5 49.5 45.1 85.9 S.N: 73 Shore base Office Trial S.N: 72 Standard practice of calibrating sound level meter before and after measurement was carried out for all measurement locations. 5.2 Weather Conditions Since environmental noise measurements are conducted outdoors, it was important to have clear weather during the survey period. The survey was carried out in clear weather conditions at all locations with no adverse conditions impacting or disrupting the survey. 5.3 Main Survey Runs The main survey runs were conducted for durations of at least 9 hours at each location. Start time at each location was 08:00 (+/- 5 minutes). End time for each location was 17:00 (+10 to 20 minutes). Noise measurements taken at the Shore base occurred on a crew change day (Wednesday July 4, 2012) for offshore personnel and hence the level of aviation activities on the said day was higher than normal leading to the recording of high decibel levels. On the same day, the base fire alarm was triggered around 9am but that did not produce the LAFmax for the two Shorebase measurement positions. 11 | P a g e The measurement conducted at the Chemical facility occurred at a time when lime discharge was occurring at the port. There was heavy haulage trucking activities within the vicinity of the measurement position. The trucks were being loaded with lime for haulage out of the port. At the Airport ridge staff house residential reference location, a construction related activity (gravel spreading) was occurring during the measurement period. This was going to significantly influence the db(A) measurements for this position. 5.4 Noise Data Analysis Noise patterns: Noise patterns refer to the temporal nature of a noise with respect to time of exposure and the level of exposure. Types: Continuous noise is produced for relatively long periods of time and usually at the same decibel level. Intermittent noises are those that are produced for short periods of time but on repetitive basis. Aircraft and helicopter take-offs and landings are examples of intermittent noises. Impulse noises are those that last for only a very short period of time. Impulse noises may include rifle firings and similar sounds. The noise pattern from the crane operating at the Shorebase could be described as continuous. Vehicular traffic, aircraft take-offs and landing at the survey sites could be described as intermittent. The level of repetitiveness of this noise source cumulatively over the survey period may approximate noise pattern to be continuous. Bird scare gun fire sound pattern at the Takoradi airport runway could be described as impulsive but its repetitive/periodic nature throughout the day makes it intermittent. Generally, the noise sources and decibel level measurements at all locations did not have the tendency to cause annoyance within the ambience as they were not tonal. The noise was typically broadband at all locations and by the zoning classification as either commercial or industrial, potential noise receptors have adjusted to the background noise levels generated by the sources. However, the noise generated during helicopter take-offs and landings had the characteristics (intensity and loudness) to cause annoyance or disturbance to close-by offices. 12 | P a g e Table 7: Survey sites description and noise zone classification Sites Site Description and Activities Main Noise Sources Shore Base The Tullow Logistics Base is located within the Takoradi Airforce Base which also accommodates the Takoradi domestic airport. The Logistics base provides warehousing, office accommodation and support to the offshore operations. The airforce base is host to other oil and gas operators such as Kosmos and Hess. The location of the Shore Base is as shown in figure 4. The site is approximately 5 ha and currently light industrial uses. The identifiable noise sources within the Shore base can be outlined as follows: Zoning Classification: D (Light Industrial) Shore Base - Pipeyard The pipeyard within the Logistics base is the storage and lay down area for tubulars and other sizeable offshore equipment and hardware such as riser sections and drill strings. 1. Aviation operations (aircraft taxying, take-offs and landings at the Takoradi Airport) 2. Bird scare gun fire sounds to drive birds off runway 3. Vehicular traffic (trucks and cross country vehicles and saloon cars) 4. Crane operations at the pipeyard (loading and offloading of tubulars, movement and stacking) Noise sources within this section of the Shore base are same as above. Lifting operations by cranes is carried out at this location. The pipeyard runs parallel to the runway (see figure 5) Zoning Classification: D (Light Industrial) Takoradi Commercial Port – FPSO Chemical Support Facility FPSO chemical support facility is located at Wharf 6 of the Takoradi Commerical Port (see figure 6). The facility is used for the decanting of bulk production chemical supplies into units suitable for transfer to the FPSO. The identifiable noise sources within the port arises from normal port operations which include docking and undocking of ships, crane loading and offloading of cargo, haulage trucks traffic noise, ship horns and siren alarms etc. Zoning Classification: C2 (Commercial) Airport Ridge Staff House (Takoradi) – Residential Reference Location This is one of the main Tullow residential facilities for staff working in Takoradi. It has six houses in a shared compound (see figure 7). Zoning Classification: A (Residential) 13 | P a g e Vehicular traffic arising from pick-up and drop-off of staff at various times in the day. Table8: Onshore Environmental Noise Survey Results Measurement Positions Period LAeq EPA permissible Limit for zones dB Comments/Remarks LAmin dB(A) LAmax L10 L90 dB dB dB 1 Shore base Pipe yard 0800 – 17:00 63.0 70 dB(A) measurements here were within limits 38.0 90.1 66.5 42.5 2 Shore base - Office 0800 – 17:00 72.1 70 dB(A) measurements here exceeded limit marginally. 43.0 87.2 77.5 50.5 3 Takoradi Port – FPSO Chemical Facility 0800 – 17:00 73.0 75 dB(A) measurements here was below the limit. 55.8 99.0 65.5 62.0 4 Residential reference – Airport Ridge staff house 0800 – 17:00 69.7 55 dB(A) measurement for the residential location was exceeded significantly i.e. > 10 dB. This was due to ongoing construction works on site at the time of survey. 41.9 100.9 70.0 45.5 14 | P a g e Noise data graphical illustration and analysis If non-steady noise is to be described, it is necessary to know both its level and degree of fluctuation. LA 10 is the level exceeded for 10% of the time and as such gives an indication of the upper limit of fluctuating noise. Similarly L90 gives an indication of the lower levels of fluctuating noise. It is often used to define the background noise. L10: This was highest at the shorebase office (77.5 dB) and lowest at the chemical facility (65.5 dB). The high value for the shorebase office location is mainly attributable to the proximity of the office to the helipad – helcipoter take-offs and landing being the highest noise source experienced. L90: This statistical parameter which represent background noise levels was highest at the FPSO chemical facility (62.0 dB) and lowest at the shorebase pipeyard (42.5 dB). This is an indication that the pipeyard is generally quite. 15 | P a g e LA max: The residential facility recorded the highest peak noise level (100.9 dB) but this can be attributed to the construction activity at the time of the survey. The lowest LAmax was recorded at the shorebase office position (87.2 dB). LA min: The shorebase pipeyard recorded the lowest LAmin value (38.0 dB) and the highest was at the FPSO chemical support facility (55.8 dB) 5.5 Potential Impacts of environmental noise exposure Noise level or dose determines the human health impact. Environmental noise exposures are typically less than occupational noise exposures. Environmental noise can be a general stressor. Health ramifications such as hearing loss, permanent and temporary threshold shifts, ear pain and tinnitus are typically associated with occupational and not environmental noise. In contrast, interference with speech, perception of noise, performance effects, annoyance and psycho physiological effects may be associated with environmental noise. There are continuous and impulse sound pressure levels that pose an immediate threat to health and welfare. For continuous sound, those exposures are 90 dB for 24 hrs, 93 dB for 12 hrs, 96 dB for 6 hrs, 99 dB for 3hrs, 102 for 1.5 hrs, 105 dB for 45 minutes and 108 for 22 minutes (USEPA Publication, 1973, Public health and welfare criteria for noise). These scientific findings imply that none of the locations surveyed have noise levels that pose immediate threat to health and welfare. For impulse sound pressure levels, the exposures are based on sound levels and the number of repetitions per 24 hr period. For impulsive sound pressure levels, the exposures are 1 repetition at 145 dB, 10 repetitions at 135dB and 100 repetitions at 125 dB. Again sound levels measured at the various survey sites were significantly lower than these levels to cause immediate health impacts. 5.6 Noise Control measures Noise control measures are dependent on the sound level and the frequency. Noise control can be achieved with barriers or enclosures. Another factor in noise reduction is distance. Doubling the distance from a source reduces the sound level by 6dB. (Irwin JD, Graf, ER: Industrial noise and vibration control, 1979). Appropriate hearing protection should be worn for occupational noise exposures in the work environment. E.g. personnel involved in tarmac aviation operations, crane operators etc. 5.7 Investigative Run Helicopter take-offs and landings are the highest noise sources at the shorebase and presents the highest exposure to staff in the Shorebase office. The shorebase office is approximately 100m away from the helipad and the closest point on the block is the aviation office. For this reason, the aviation office had been fitted with a triple glazed glass window to act as a sound barrier. A one (1) hour investigative run was conducted to ascertain the effectiveness of the sound barrier installed to reduce noise level inside the office. This measurement run was conducted during a helicopter takeoff. The measured dB(A) value inside and outside office were 62.5 dB and 75.5 dB respectively. The difference was 13 dB which is very significant in terms of noise exposure reduction. This triple glazed glass window proved effective as a sound barrier. 16 | P a g e 6.0 Conclusions and Recommendations Environmental noise exposures are typically less than occupational noise exposures. Generally, the noise sources and decibel level measurements at all locations did not have the tendency to cause annoyance within the ambience as they were not tonal. The noise was typically broadband at all locations and by the zoning classification as either commercial or industrial, potential noise receptors have adjusted to the background noise levels generated by the sources. However, the noise generated during helicopter take-offs and landings had the characteristics (intensity and loudness) to cause annoyance or disturbance to close-by offices. In general terms, there are some continuous and impulse sound pressure levels that pose an immediate threat to health and welfare. However measurements conducted at the various survey positions did have noise levels significantly lower than the thresholds that could cause immediate threat to health and welfare. Nevertheless, noise protection is recommended at all times for occupational noise exposures to prevent potential long-term hearing loss. Again it was found at that the intervention to reduce noise levels within offices with the installation of triple glazed glass windows proved effective. It is important to note that this one time survey cannot be used to characterise the ambient noise profile at the various locations. The results obtained reflect the environmental noise conditions at the time of the survey 3-6 July 2012. Repetitive survey may be required to comprehensively define the noise profiles at the various locations. It is recommended that this noise survey be conducted at least twice a year and in some cases in response to particular complaints from local community about environmental noise sources related to TGL operations. 17 | P a g e Appendices Appendix A: Location maps showing measurement positions for the various sites Figure 4: Map and picture showing the measurment position infront of the Shorebase Office Title Latitude Longitude Date Stamp Attributes Shore base - Close to the Heliport N 4° 53' 47" W 1° 46' 19" 7/4/2012 18 | P a g e Figure 5: Map and picture showing the measurement position in the Shore base pipeyard Attributes Title Latitude Longitude Date Stamp Shore base - Pipeyard N 4° 53' 52" W 1° 46' 18" 7/4/2012 19 | P a g e Figure 6: Map and picture showing the measurement position in the FPSO Chemical Facility Attributes Title Latitude Longitude Date Stamp Takoradi Port - FPSO Chemical Facility N 4° 53' 11" W 1° 44' 11" 7/5/2012 20 | P a g e Figure 7: Map and picture showing the measurement position in the staff house compound Attributes Title Latitude Longitude Date Stamp Airport Ridge Staff House N 4° 54' 21" W 1° 46' 39" 7/5/2012 21 | P a g e Appendix B: Noise level time history logs taken at the various measurement positions 22 | P a g e 23 | P a g e 24 | P a g e 25 | P a g e