Noise Injury - Ears, Audiology and Hearing Impairment

Craig Mixon, Ed.D, has published a comprehensive chart/poster called The Symptoms & Side Effects of Force-Feeding Noise into the Domestic Environment. Clicking on that link brings you to a pdf file of the document where you can read, download or print the poster. It is disturbing stuff but it clearly illustrates the possible effects of living with noise in the home.

Is the noise from laminate flooring being force fed?

My opinion is yes - because the victim of the noise pollution has no control over the noise. The persons who control the noise are the persons who do not adequately soundproof the flooring and who are intentionally or unintentionally force feeding noise into someone else's domestic environment.

Semantics aside - the real fact is the people are living in their homes and being subjected to impact noise on a daily basis and they are at risk of developing Noise Injury.

As the chart shows, there are many ways in which noise can injure a person - both physically, emotionally and psychologically. In researching this article I realised that I could not properly cover Noise Injury in one entry and decided to break down Noise Injury into a series of articles covering the various topics. It seems logical to begin with the ears, hearing and auditory injury since this is the most obvious and recognisable route into the body that noise takes.

The Handbook of Clinical Audiology describes three changes in hearing due to noise:

• Noise induced temporary threshold shift (NITTS)
  
• Noise induced permanent threshold shift (NIPTS)
  
• Acoustic Trauma

Noise Induced Temporary Threshold Shift

Have you ever noticed the way your ear feels or reacts when someone bursts a balloon close to you? You might experience a sense of your ear filling up, temporary reduction in hearing others sounds and you may even experience tinnitus/ringing in the ears. This is noise induced temporary threshold shift and it is the way the ear deals with some sounds.

In relation to the impact noise created by laminate flooring, a person may experience NITTS many times in a day over a long period of time. The Handbook of Audiology finds that if the NITTS exceeds 20dB* and/or the exposure is moderate but occurs over an extended period of time then recovery may be delayed.

Noise Induced Permanent Threshold Shift

NIPTS occurs when there is a lack of recovery from NITTS and is a slow and progressive condition. It may take years of repeated exposures before the person is aware of any change in hearing ability - by which time the damage is done and it is too late.

Acoustic Trauma

It is unlikely that laminate flooring noise would result in Acoustic Trauma since the range of noise prevalent in causing acoustic trauma is 2000Hz and 6000Hz and is outside the range of documented sound produced by laminate flooring.

Tinnitus

Tinnitus is best described as ringing in the ears when there is no external sound stimulus. It is associated with noise induced hearing loss.


It is not unreasonable to consider the possibility that long-term exposure to the intermittent impact noise created by laminate flooring could result in damage to hearing.


*DEFRA find that noise levels produced by laminate and hardwood flooring surfaces range between 59 dB and 72 dB

Lack of Legislation = Lack of Solution

1. Start building a relationship with your neighbour
2. Have a quiet word about the problem
3. Have a stronger word: explain the impact on your family
4. Employ mediation services
5. Contact your local authority
6. Contact abatement societies
7. Take legal action

Above is the suggested trail for resolving a neighbour noise problem as posted by Noise Concern. Unfortunately, lack of any legislation regarding laminate flooring and noise means that any and all of these options could be fruitless.

Options 1-3 involve the owner of the flooring being willing to take responsibility for the noise issue. If the owner of the flooring is not willing to do this, has been led to believe an underlay is adequate, or has actually been told by an Environmental Health Officer that their neighbour "is just experiencing impact noise" - then any and all of the following options may be pointless suggestions.

Mediation Services are, by definition, meant to be impartial and unbiased. If people are not required by law to adequately soundproof laminate flooring, mediation appears to be simply a way for local authorities to wash their hands of the problem. The DEFRA study also noted that “Mediation was the most widely attempted mechanism for dealing with impact noise problems however it had the lowest success rating.”

Since it does not appear that any local authority, nor any law, considers laminate flooring noise to be a nuisance, there is little hope of successful legal action. Research for this blog has thus far not found any examples of a case where a successful resolution to a laminate flooring noise problem was procured through the courts.

Essentially the law supports individuals in adversely affecting the health and lifestyle of neighbours, leaving people who live with this noise problem with no hope of a solution.

Laminate Flooring Underlays

The perception that the installation of an underlay equates to soundproofing is flawed - particularly with legacy flooring that has been in place for several years.

DEFRA suggest that manufacturers of laminate flooring and underlays be investigated for their claims regarding noise reduction - “It should be clear to anyone with a basic understanding of building acoustics that these claims are, at best, misleading, but in most cases quite meaningless.”

Whilst the underlay may show in tests that it reduces noise transmission, this is often only regarding the underlay product by itself and does not illustrate the effects of placing a laminate or other hardwood surface on top.

"Many of the underlays when tested in isolation provide very good levels of impact sound insulation, in some cases twice as much a carpet on its own. However, the addition of the hard floor finish drastically reduces the impact performance."

Given the misleading claims of the underlay manufacturers themselves, it is not surprising that owners of the flooring believe that they are not creating noise because they have used an underlay.

Since there is a lack of legislation surrounding the installation of laminate flooring, there is no requirement for persons to use any underlay at all. The author was informed by an Environmental Health Officer that a person could quite legally install laminate on bare floorboards with no underlay.

Laminate Flooring Noise and Sleep Disturbance

"WHO guidelines say that for good sleep, sound level should not exceed 30 dB(A) for continuous background noise, and individual noise events exceeding 45 dB(A) should be avoided."

The DEFRA study on Laminate and Hardwood flooring says: "Impact noise from footfalls** is quite unique as the exposed dweller feels they are unable to avoid it, no matter which room they are in. Impact noise from footfall can occur at all times of the day and night dependent on the living style and sleep patterns of the upper occupants."

On the same page of the DEFRA study Table 3.1 displays the typical impact performance of floors in various dwellings. The table shows impact noise transmission of hardwood flooring ranges between 59 dB and 72 dB.

If it is the case that simple footfall transmissions at their lowest level measure 59 dB and WHO guidelines state that individual noise events exceeding 45 dB should be avoided during sleep, then it is not unreasonable to suggest that laminate flooring creates a noise problem that causes sleep disturbance.

**As stated in a previous post, footfall is only one type of impact sound experienced by those living below properties where laminate flooring has been installed.

How Low Frequency Noise Affects Health

"In humans the effects studied have been on the cardiovascular and nervous systems, eye structure, hearing and vestibular function, and the endocrine system. Special central nervous system (CNS) effects studied included annoyance, sleep and wakefulness, perception, evoked potentials, electroencephalographic changes, and cognition. Reduction in wakefulness during periods of infrasonic exposure above the hearing threshold has been identified through changes in EEG, blood pressure, respiration, hormonal production, performance and heart activity." (From DEFRA Study on the Health Effects of Low Frequency Noise)

This suggests that daily exposure to the Low Frequency Noise generated by laminate flooring could have serious health implications. The World Health Organisation (WHO) have also produced studies relating to the health effects of exposure to noise. The WHO document, Guidelines for Community Noise, contains a chapter detailing the Adverse Health Effects of Noise detailing the following:

• Noise-induced hearing impairment
• Interference with Speech Communication
• Sleep disturbance
• Cardiovascular and physiological effects
• Mental health effects
• The effects of noise on performance
• Effects of Noise on Residential Behaviour and Annoyance