Overview

Since 2004 NVM limited have provided the supply of vibration and noise monitoring instrumentation, embankment monitoring equipment , geotechnical instrumentation, and environmental data monitoring and acquisition services, to local authorities, universities and engineering training colleges and the majority of Ireland’s leading construction sector companies.

With over 30 years service experience within NVM we provide a first class service to our clients.

NVM Ltd can provide companies with

a complete environmental

monitoring service.

Noise Assessments

Environmental noise surveys and assessment

Noise pollution (or environmental noise) is displeasing human, animal or machine-created sound that disrupts the activity or balance of human or animal life.

The source of most outdoor noise worldwide is transportation systems, including motor vehicle noise, aircraft noise and rail noise.

Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential area.

Other sources of indoor and outdoor noise pollution are car alarms, emergency service sirens, office equipment, factory machinery, construction work, grounds keeping equipment, barking dogs, appliances, power tools, lighting hum, audio entertainment systems, loudspeakers, and noisy people.

NVM Ltd undertake environmental noise surveys in accordance with the required relevant EPA and British guidelines and standards, which include some of the following documents;

• BS 5228: 2009 +A1 2014: Code of practice for noise and vibration control on construction and open sites – Part 1: Noise
• ISO 1996-1:2016 “Acoustics – Description, measurement and assessment of environmental noise Part 1: Basic Quantities and assessment Procedures”

Evironmental noise note:

In the European Union about 40% of the population is exposed to road traffic noise with an equivalent sound pressure level exceeding 55 dB(A) daytime, and 20% are exposed to levels exceeding 65 dB(A).

When all transportation noise is considered, more than half of all European Union citizens are estimated to live in zones that do not ensure acoustical comfort to residents. At night, more than 30% are exposed to equivalent sound pressure levels exceeding 55 dB(A), which are disturbing to sleep.  Noise pollution is also severe in cities of developing countries.  It is caused mainly by traffic and alongside densely travelled roads equivalent sound pressure levels for 24 hours can reach 75-80 dB(A).

Occupational noise (Noise At Work) assessments

NVM Ltd understand that organisations today have a fundamental responsibility to minimize the impact of excessive noise exposure at work.

Most companies understand the requirement to identify hazards of noise and are willing to conduct periodic noise surveys as part of their company health and safety procedures, but this is only the first step in management of occupational noise.

Beyond hazard identification there is a requirement to manage exposure to noise on a day-to-day basis. This requires a comprehensive system of policies, procedures and guidelines aimed at reducing the potential for noise induced hearing loss (NIHL) to practical levels.

NVM Ltd can provide occupational noise management, to help support organizations with their occupational noise assessments including:

Click here for a free quotation on your premises.

Hearing protection suitability assessment

Noise is not a new hazard. It has been a constant threat since the industrial revolution. Too much noise exposure may cause a temporary change in hearing (your ears may feel stuffed up) or a temporary ringing in your ears (tinnitus). These short-term problems usually go away within a few minutes or hours after leaving the noise. However, repeated exposures to loud noise can lead to permanent, incurable hearing loss or tinnitus.

NVM Limited recommend removing hazardous noise from the workplace whenever possible and using hearing protectors in those situations where dangerous noise exposures have not yet been controlled or eliminated.

Exposure to noise levels at 80 decibels (dB) or higher for eight hours or more per day puts your hearing at risk.

But the good news is ... hearing loss is preventable. Every employee on the shop floor should have some form of hearing protection. This could be anything from simple foam earplugs to custom-made headsets. the best hearing protection device is the one you wear and wear correctly.

Helpful hints

Some steps you can take to protect your hearing include:

• Wear protective devices
• If working within areas of high level noise, try and limit your exposure to loud noise at every available chance
• Be aware of noises around you and within the work area.
• Use caution when listening to headphones
• Have your hearing tested regularly if you are at risk for hearing loss. (Audiometric testing)
• Check with your employer about hearing protection and noise reduction methods.

Other Services Provided

• IPPC and IE Compliance (Environmental Noise) Monitoring
• Environmental Impact Statements (EIS)
• Sound Installation Tests

Geo-technical Instrumentation

Geo-technical monitoring has become a major requirement in all aspects of today's construction industry.

Requirements for instrumentation that can be used in the continuous monitoring of embankments, structural settlement , load and stress testing, means clients are now looking for reliable instrumentation that is proven in today's harsh working environments.

NVM have a proven record in the supply, installation and training of the following geo - technical instrumentation.

Inclinometer systems

Inclinometer systems can be used to measure deflections in piles and to ensure that holding anchors put in place are performing within their tolerances, and are not affected by ground movements.  In this way they can be of assistance to design teams by confirming that projects are working with in the agreed limits put in place prior to construction.  Inclinometer systems are used in the monitoring of piling operations to detect slope zones of movement or displacement and to establish if the movement is constant, accelerated or responding to any remedial measures put in place by the contractor.

The main objective of measuring inclination is to predict any type of movement so that preventative measures can be undertaken and the project can move forward with out any safety or build concern.

Applications for vertical inclinometers include:

• Monitoring slopes and landslides to detect zones of movement and establish whether movement is constant, accelerating, or responding to remedial measures.
• Monitoring dams, dam abutments, and upstream slopes for movement during and after impoundment.
• Monitoring the effects of tunneling operations to ensure that adjacent structures are not damaged by ground movements.

Embankment monitoring

The construction of motorway or rail embankments and levees often require instrumentation to monitor the progress of consolidation and to determine whether the embankment is stable or if there is movement that it is within agreed design tolerances.

Geo-technical Instrumentation can also be utilized to monitor the effectiveness of vertical drains used to accelerate consolidation in embankment construction or on any project where the risk of slope destabilisation is evident.

Typical Instruments used to measure Embankment Movement include:

Inclinometers, Piezometers, Pressure Cells, Settlement Systems, Rod Extensometers

All the above can be recorded both manually or automatically depending on the site requirements.

A system could consist of piezometers installed on the upper slopes of the embankment, tiltmeters placed on retaining walls, and inclinometers which are installed through the slip plane. The piezometers monitor pore-water pressure, the tiltmeters monitor rotation of the retaining walls, and the inclinometers monitor subsurface movements.

Piezometers

There are numerous applications for piezometers and thus there are many different types of piezometers - (standpipe, pneumatic and vibrating wire) all are used to measure pore water pressure to establish safe rates of fill or excavation.

Typical applications for piezometers include the following

• Monitoring pore water pressures to evaluate slope stability.
• Monitoring dewatering systems used for excavations.
• Monitoring ground improvement systems, such as vertical drains and sand drains.
• Monitoring pore pressures to check the performance of earthfill dams and embankments.
• Monitoring pore pressures to check containment systems at landfills and tailings

Data loggers

Data loggers are an electronic devices that record data over time or in relation to location either with a built in instrument or sensor or via external instruments and sensors.  They are based on the principle of a digital processor (or computer) and are small, battery powered, portable, and equipped with a microprocessor, internal memory for data storage, and sensors.  They can be used to interface with a personal computer and utilize software to activate the data logger and view and analyze the collected data, while others have a local interface device (keypad, LCD) and can be used as a stand-alone device.

One of the primary benefits of using data loggers is the ability to automatically collect data on a 24-hour basis.  Upon activation, data loggers are typically deployed and left unattended to measure and record information for the duration of the monitoring period. This allows for a comprehensive, accurate picture of the environmental conditions being monitored, such as air temperature and relative humidity.

Distribution

In 2009 NVM Ltd acquired the sole Irish distribution of Geosense Instrumentation allowing them to provide their clients with state of the art monitoring instrumentation and an in-depth bank / library of geo-technical instrumentation knowledge from one of the worlds leading instrumentation suppliers. Download the latest Geo-Sense catalogue.

Training

NVM / Geosense can provide in house training courses both in our offices in Drogheda or at our clients premises, alternatively training courses can be completed in the Geosense head office in the Uk.  These training sessions can provide clients with a basic knowledge on instrumentation allowing the client to be in command of the instrumentation in use on site while being safe in the knowledge that backup is at hand at the end of the phone through NVM.

Settlement cells

Settlement cells are used to monitor settlement and heave in soils.

Typical applications include:

• Monitoring settlement or heave in embankments and embankment foundations.
• Monitoring subsidence due to tunneling and mining.
• Monitoring consolidation under storage tanks.
• Monitoring settlement due to dewatering or preloading.
• Monitoring settlement in fills.

Tilt meters are used to monitor changes in the tilt of a structure.  Tilt changes may be caused construction activities, such as excavation, tunneling, and dewatering, that affect the ground that supports the structure.  Changes in tilt may also result from loading of a structure, such as the loading of a dam during impoundment, the loading of a diaphragm wall during excavation, or the loading of a bridge deck due to wind and traffic.

Tilt

Typical applications for tilt meters include:

• Monitoring stabilization measures, such as pressure grouting and underpinning.
• Monitoring structures for the effects of tunneling and excavating.
• Evaluating the performance of bridges, beams, and dams under load.
• Monitoring the stability of structures in landslide areas.
• Monitoring the deflection and deformation of retaining walls.
• Monitoring convergence and other movements in tunnels.
• Providing early warning of threatening deformations, allowing time for corrective action to be taken or, if necessary, for safe evacuation of the area.

Overview

Contractors need to ensure all  necessary precautions to contain dust arising from excavations and construction works shall be taken to prevent a nuisance being caused to occupiers of buildings and properties in the vicinity of their works.

The Bergerhoff Method is described in the standards BS1747 Part 1: Methods for the measurement of air pollution. Deposit gauges, and VDI 4320 Part 2 Measurement of atmospheric depositions - Determination of the dust deposition according to the Bergerhoff method (the latter published by the German Engineering Institute).

Dust Deposition Rate is normally measured by gravimetrically determining the mass of particulates and dust deposited over a specified surface area over a period of one month (30 days +/- 2 days). The results are expressed as dust deposition rate in mass per unit area per day (mg/m2-day).

The Bergerhoff Gauge dust monitoring instrument is used on location and designed to measure for dust deposition, usually quoted as mg/m2/day.

Equipment Hire

NVM Limited has a proven record in the supply, installation of hire instrumentation. Since 2004 we have provided cost efficient hire monitoring solutions to hundreds of projects both large and small, in most cases reducing the costs of purchasing instrumentation for specific projects.

Monitoring Service

NVM Limited provide a dedicated, valued monitoring service tailored to our customers’ needs by providing uninterrupted data collection, expert advice and state of the art instrumentation. We are able to surpass our customers’ requirements, allowing them to continue with their role on site without the concern of providing efficient data to the relevant bodies.

Call 041 983 7435 or email sales@nvm.inview.ie for a Quote Today.

Vibration Monitoring and Assessment

Introduction

Vibration monitoring is an essential part of day to day site management in the construction industry. Guidance notes on instrument placing and monitoring guidelines can be found  in monitoring standars such as;

• BS 5228: 2009 +A1 2014: Code of practice for noise and vibration control on construction and open sites – Part 2: Vibration.
• ISO 1996-1:2016 “Acoustics – Description, measurement and assessment of environmental noise Part 1: Basic Quantities and assessment Procedures”
• BS 7385 – “Evaluation and measurement for vibration in buildings – Part 2: Guide to damage levels from ground borne vibration” (1993);

Concern in relation to the potential for structural damage and nuisance caused by the use of explosives during quarrying and mining and also the use of piling equipment on construction sites with that of alternative heavy construction activity as always been high on the agenda of many construction companies, Local Authorities and the general public.

NVM Ltd can provide both the expertise and equipment to complete assessments to ensure all allowable and acceptable levels are at proposed or existing guidance levels.

Vibration Surveys

NVM Ltd can complete baseline / background monitoring and assessment surveys to establish existing vibration levels and help companies in their planning of pre–works monitoring programs. Complaints about vibration caused by traffic, pile-driving, and blasting are commonplace within the construction industries.

Recognised criteria for assessment of vibration impacts is peak particle velocity which is measured in three orthogonal directions transverse, vertical and longitudinal (x,y and z axes) this measured in millimetres per second (mm/s).

“On typical piling and construction projects at well - constructed properties - Typical values of between 10 mm/s and 30 mm/s can be tolerated without serious damage implications, however the figure with which the human body is sensitive to and capable of perceiving vibration levels at is much lower –human perception can be as low as 0.5 to 2 mm/s in the vertical direction which is the main reason why complaints are commonplace.”

Construction Applications

• Structural vibration monitoring
• Prediction of ground-bourne vibration
• Airover pressure from large scale demolition projects risk analysis
• Piling monitoring programs

Quarries and Mining applications

• Measurement and assessment of HGV and rail movements
• Determination of safe working distances
• Residential monitoring programs
• Blast monitoring
• Quarry and IPPC license procedures

Occupational Surveys - HAV and Whole Body Assessment

• Guide To Hand Arm Vibration

New legislation regarding the protection of employees and employers in the field of vibration is now in force in the Republic of Ireland.

The Control of Vibration at Work Regulations 2005

This requires employers to monitor and implement, if necessary, strategies to ensure that their employees are not exposed to vibration levels that may cause pain, discomfort or adversely affect their lives outside of work, or impede their ability to perform their duties properly.

The groups who may be at risk are;

• Employees who are exposed to Hand Arm Vibration through the use of hand held tools like for example grinders, impact drills, cutting tools, etc.
• Employees who are exposed to Whole Body Vibration through the operation of heavy plant and machinery such as diggers, dumpers, excavators, fork lift trucks, grass cutting machines, etc.

NVM Ltd offer a comprehensive testing and reporting service which conform to the ISO 8041:2005 and is in accordance with the Control of Vibration at Work Regulations 2005.

Summary of HAV

Hand-arm vibration syndrome, once commonly known as vibration white finger, is a type of repetitive stress injury that can result in permanent damage to your fingers, hands, and lower arms.
It can develop after prolonged exposure to hand-held, vibrating tools. Because this describes many different types of machinery, hand-arm vibration syndrome, or HAVS, can affect a wide variety of people and professions.

HAVS can occur due to the use of several different types of equipment, including:

• Jackhammers
• Concrete vibrators and levelers
• Chainsaws
• Needle guns
• Chipping tools
• Polishers
• Sanders

Over time, the vibrating can affect your circulation, nerves, and other tissue. Thus, there are three different indicators of HAVS.

First, you may notice a condition similar to Raynaud's phenomenon. This is where people derive the nickname "white finger." With this symptom, exposure to cold weather or cold objects can make your fingers turn a very stark white.

Next, they turn blush as they lose their oxygenated blood supply. Lastly, circulation rapidly returns, turning fingers bright red.

Next, vibrating tools can also interfere with your nerves. This can leave you with painful tingling as well as numbness in your fingers. The numbness can disrupt your ability to handle fine tasks, such as fastening buttons.

Lastly, the vibrations can also cause damage to your muscles, bones, and joints through your fingers, hands, and lower arms. This may cause you to suffer from aches and pains throughout your arms.

In 2005 the Health and Safety Authority (HSA) estimated that 13% of workers in Ireland are exposed to HAV in the workplace, and about 40% of those who are exposed are exposed to levels of vibration where there are clear risks of developing disease.

HAVS is preventable, but once the damage is done it’s irreversible and the cost to employees and employers who do not take action could be very high.

The regulations introduced Action and Limit Values for HAV and action to reduce the level of personal exposure is required if these values are reached or exceeded.

Exposure Action Value (EAV)

This level is set at 2.5m/s² averaged over an 8 hours working day, where employers are required to put in place technical and organisational measures to reduce exposure.

Exposure Limit Value (ELV)

This level is set at 5.0m/s² averaged over an 8 hour working day, where employee exposure is not permitted to exceed.

Summary of WBV

Have you ever tightened your grip on the steering wheel, dashboard or seat anticipating the next pothole or next obstacle? Over a prolonged period of time, this type of exposure takes a toll on the body. Occupations that require driving long distances or operating heavy equipment expose workers daily to low-frequency vibrations generally less than 100 Hz. Exposure to these vibrations can cause serious physical problems ranging from chronic back pain to nerve or organ damage.

Research on truck drivers and heavy equipment operators indicates that intense, long-term whole-body vibration increases risk to the spine.

Whole-body vibration is caused by twisted sitting postures combined with vibration. The combination increases stress and load on the neck, shoulder and lower back. To compensate for the discomfort from vibration, drivers should change their position. However, if the assumed position is incorrect, the stress may be increased.

This often occurs when operating equipment which causes constant physical vibration such as occurs when driving off-road vehicles or forklifts.

Whole-Body Vibration Exposure

As vibration is transmitted to the body, the effect of the vibration can be amplified by factors such as body posture, type of seating and frequency of the vibration. Individual human body parts have their own resonant frequencies. This is why after a long drive we continue to feel as if we are still moving even after the vehicle has stopped. Vibration from engines can agitate the body to the point of causing micro fractures in the vertebrae, disc protrusion, nerve damage and acute lower back pain.

Short-term exposure vibration causes only small physiological effects such as a slight degree of hyperventilation and increased heart rate. Vibration also causes increased muscle tension from voluntary and involuntary muscle contraction. Muscles become tense in order to dampen the vibration. Examples of this type of tension would be having your foot fall asleep while pressing the accelerator pedal or experiencing a tingling sensation in your hands from gripping a steering wheel too tightly.

• Low-frequency vibrations of moderate intensity can induce sleep.

• Higher frequencies have the opposite effect.
• Vision can also become blurred because of the movement of the image on the retina.

With advancements in transportation, we often travel longer distances at faster speeds. Whole-body vibration research is now focusing on determining the vibration and exposure levels that initiate physical and mechanical changes in the body.

Exposure Determination

To determine possible whole-body exposure to workers, ask the following questions:

• Is the worker exposed to whole-body vibration while sitting in a vehicle?
• Does motion and/or vibration cause the worker to hold on to the steering wheel or another support for stability while standing or sitting?
• Does the worker complain of pain, discomfort or fatigue in the back, buttocks or feet because of jolts or vibration?
• Does the worker bounce when the vehicle is in operation?
• Is the worker in an awkward position?
• Is the seat on the vehicle properly secured and maintained?

Control Measures

If your workers are exposed to whole-body vibration, engineer the problem out by installing newly designed seats and suspension systems. If that is not practical, the next best thing is to institute work practice controls to reduce or minimize the vibration.

To control the amount of whole-body vibration, the following work practices and administrative controls can be implemented:

• Reduce travel speed to reduce vibration levels;
• Require rest breaks to avoid constant continued exposure.
• Obtain information on equipment vibration and recommended maintenance schedules from the vendor;
• Minimize the vibration created between floor ramps and vehicles by maintaining ramps and dock levellers;
• Improve vehicle suspension and use vibration isolation or dampening for seating to reduce vibration transmission; and
• When appropriate, workers should incline the backrest up to 10 degrees and use lumbar support.

Summary

Whole-body vibration most often affects occupations that require prolonged driving.

Research shows that continuous exposure to vibration can be detrimental to the body. Any intervention such as isolating the driver, using lumbar support and armrests or repairing roads can help reduce whole-body vibration. The key is to take action by eliminating or reducing the exposure to whole-body vibration.