Speaking of noise risk in theater is not a simple thing and it is precisely for this reason that the legislature has deferred to a year from the date of entry into force of Legislative Decree no. 81/2008, the issuance by the Permanent Conference for relations between the State, the Regions and Autonomous Provinces of Trento and Bolzano, specific guidelines that will cover just the music industry and recreation.
The above however does not obviate an accurate assessment and measurement for work at that stage of its type can be compared to the work site and / or workshop. In
stage productions usually come already built, but that happens, especially on installations metal (in recent years also used more frequently than traditional wood) are both necessary adjustments during the installation and dismantling. All this involves the use of tools such as grinders, drills, welders, etc. ...
Who uses these tools? For small adjustments are usually technical drivers (often lack information and training) are working to use these tools while for complex installations that require mounting the stage, are often contractors specializing in the manufacture of iron. The above represents what can happen in the work on the stage so that noise is not without risk.
Surveillance Hearing health was certainly the visits that are made in particular to technical machinery and equipment but the same should be extended to all those who work in a stage.
Let's see what the law says about the risk that noise is still often overlooked but is the hearing loss they may cause one of the first entries in the list of occupational diseases.
It is estimated that the costs for hearing loss in Europe amount to about 10% of all those for occupational diseases. For these reasons the European Council disciplineto matter to fifteen years on expanding its scope and providing a review of the threshold values \u200b\u200bthat take into account progress in technology and scientific knowledge.
In Italy the noise is still the cause of occupational diseases reported INAIL more frequently. Occupational disease by physical agents cause more than 13,000 cases annually of about 26,000 total, of which the hearing loss is by far the most common disease.
The Leg. April 10, 2006, No 195 transposed the Directive 2003/10/EC on the minimum health and safety requirements regarding the exposure of workers to risks arising from noise. In connection with the reorganization
work with the enactment of Legislative Decree no. 81/2008, all matter is merged in Title VIII, Chapter II, art. Article 187. 198.
Article. 180 Leg. 81/2008 defines the first paragraph of the scope as follows:
'For the purposes of this Legislative Decree shall be construed to physical agents noise, ultrasound, infrasound, mechanical vibrations, electromagnetic fields, optical radiation, the microclimate and the atmosphere that hyperbaric may involve risks to the health and safety of workers'.
Also in reference to Chapter I, Art. 181 provides for the assessment of risks, the art. 182 contains provisions aimed at eliminating or reducing the risk at issue, Article. 183 indicates the categories of workers particularly vulnerable to physical hazards, art. 184 prescribes the obligation to provide information and targeted training, the exposed workers and their representatives in the art. 185 prescribes the obligation of health surveillance, Article. 186 shows evidence for the compilation of medical records and risk.
What is noise? We
as defining the noise as a complex set of sounds of various frequencies and duration, ie the transmission of mechanical energy through elastic means in the form of mechanical vibrations that propagate with a characteristic speed of the vehicle and result in vibrations of pressure.
A sound is an auditory sensation caused by a disruption of the equilibrium state of the air. Noise can damage the health of exposed persons (mostly hearing) or safety, masking the verbal communication and perception of audible security.
noise-induced hearing loss occurs in the first period with a hearing impairment asymptomatic and limited to mid-high frequencies and then can be extended to other frequencies, which occur so some physical symptoms (tinnitus), buzzing and dizziness. Afterwards begins the perception of a slight deafness in some instances as to be on the phone or listen to a program on TV, and by extension, be warned sharply.
Noise can also cause damage outside the hearing, sense of balance and movement, nervous system, appear on the digestive, respiratory and vascular system.
Among the definitional aspects of interest should be noted:
- peak sound pressure (p-peak) that is the maximum instantaneous sound pressure frequency-weighted "C";
- the daily noise exposure level (L-EX, 8h) [dB (A) relating to 20 nPa ] that is the weighted average function of time, the levels of noise exposure for a nominal 8-hour workday, as defined by international standard ISO 1999:1990 section 3.6. It covers all noises present at work, including work impulsive
- weekly noise exposure level (L ex-, w) which is the weighted average depending on the weather, the daily noise exposure levels for a week Rated five working days of 8 hours, as defined the international standard ISO 1999:1990 section 3.6, footnote 2.
limit values \u200b\u200band exposure action values, depending on the level of daily exposure to noise and peak sound pressure, are so 'set:
a) exposure limit value, respectively ex-L = 87 dB (A ) and p = 200nPa
-peak (140 dB (C) is referred to 20nPa)
b) higher values \u200b\u200bof action, respectively, L x = 85 dB (A) and p = 140nPa
-peak (137 dB (C) reported to 20nPa)
c) lower values \u200b\u200bof action, respectively ex-L = 80 dB (A) and p-peak = 112nPa
(135 dB (C) is referred to 20nPa).
Where, due to the intrinsic characteristics of work, exposure giornaliera al rumore varia significativamente, da una giornata di lavoro all'altra, è possibile sostituire, ai fini dell'applicazione dei valori limite di esposizione e dei valori di azione, il livello di esposizione giornaliera al rumore con il livello di esposizione settimanale a condizione che il livello di esposizione settimanale al rumore, come dimostrato da un controllo idoneo,non ecceda il valore limite di esposizione di 87dB(A) e siano adottate le adeguate misure per ridurre al minimo i rischi associati a tali attività.
Nel caso di variabilità del livello di esposizione settimanale va considerato il livello settimanale massimo ricorrente.
Il datore di lavoro, secondo quanto disposto dall'art. 190, deve valutare l'esposizione dei lavoratori al rumore durante il lavoro prendendo in considerazione in particolare:
- il livello, il tipo e la durata dell'esposizione, ivi inclusa ogni esposizione a rumore impulsivo;
- i valori limite di esposizione e i valori di azione;
- tutti gli effetti sulla salute e sulla sicurezza dei lavoratori particolarmente sensibili al rumore;
- per quanto possibile a livello tecnico, tutti gli effetti sulla salute e sicurezza dei lavoratori derivanti da interazione fra rumore e sostanze tossiche connesse con l'attività svolta e fra rumore e vibrazioni;
- tutti gli effetti indiretti sulla salute e sulla sicurezza dei lavoratori risultanti da interazioni tra rumore e segnali di avvertimento o altri suoni che vanno osservati al fine di ridurre il rischio di infortuni;
- le informazioni sull'emissione di rumore fornite dai costruttori dell'attrezzatura di lavoro in conformità alle vigenti disposizioni in materia;
- l'esistenza di attrezzature di lavoro alternative progettate per ridurre l'esposizione al rumore;
- il prolungamento del periodo di esposizione al rumore oltre l'orario di lavoro normale, in locali di cui è responsabile;
- le informazioni raccolte dalla sorveglianza sanitaria, comprese, per quanto possibile, quelle reperibili nella letteratura scientifica;
- la disponibilità di dispositivi di protezione dell'udito con adeguate caratteristiche di attenuazione.
Fatto salvo il divieto al superamento dei valori limit exposure to fluctuations in activities that involve high levels of exposure among workers, the employer may assign to such workers exposure to noise above the higher values \u200b\u200bof action, providing them with preventive measures and resulting in protection and in particular:
- the availability of personal protective equipment hearing;
- information and training;
- health checks.
In this case the measurement associated to the evaluation is limited to determining the level of noise produced by equipment in the workplace for the identification of measures of prevention and protection and to formulate a program of technical measures and organizational.
workplaces where workers may be exposed to noise above the upper action values \u200b\u200bshall be indicated by appropriate signs. These areas shall also be delimited and access to them limited where this is technically possible and justified by the risk of exposure.
The employer, if the risks arising from noise can not be avoided through preventive measures and protection must provide personal protective equipment for the hearing.
E 'provided that the employer ensures that workers exposed to values \u200b\u200bat or above the lower values \u200b\u200bof action are informed and trained in relation to the risks from exposure to noise. It 'also the duty of the employer to undergo health surveillance employees whose noise exposure exceeds the upper action values. The monitoring is carried out periodically, usually once a year or a different schedule decided by the physician in charge, with adequate reasons given in the document risk assessment and made known to the representatives for the safety of workers on the basis of risk assessment. The supervisory board, for justified reasons, may provide content and frequency of monitoring different from those provided by the physician.
Health surveillance is extended to workers exposed to levels lower than the values \u200b\u200bof action, at their request and if the physician in charge confirms their opportunities.
The employer may require derogations from the use of PPE and compliance with the exposure limit value (art. 197), when the nature of work, the use of such devices might pose a risk to health and safety of workers more than would happen without their use.
These exemptions are granted, after hearing the two sides, for a maximum period of four years by the supervisory board that has territorial jurisdiction shall also notify the Ministry of Labour and Social Welfare. The conditions for exemptions are reviewed every four years and in the event of the loss of its assumptions, apply immediately resumed the regular life.
The granting of exemptions is conditioned by the intensification of surveillance and health conditions which guarantee, taking into account the particular circumstances, that the risks are minimized. The employer shall ensure the strengthening of health surveillance and compliance with the conditions set by the exceptions.
The ISPELS has developed guidelines that address all matters pertaining to the noise hazard. Council to refer the following link for further information which was made part of this post:
www.ispesl.it / linee_guida / fattore_di_rischio / LG% 20RUMORE.pdf
The noise can be measured in two ways:
- without measuring
- with measurement
In the first case we are dealing with workplaces that often have no risk or noise, however it is very low and calculated on the basis of technical specifications of the machinery used. The thing but we must always take into account is that in the presence of multiple machines detected the noise is always the sum of individual machine noise.
In the second case the detection of noise is often advisable to make it to companies that specialize in the possession of equipment whose cost is around key figures ranging from five to ten thousand euro.
methods to assess the noise level of a worker wearing PPE:
- OBN based on levels per band octave;
- HLM based on relaxations in low, medium and high frequency-weighted sound pressure levels to A and C;
- SNR on the basis of mean attenuation across frequencies and the C-weighted
The laboratory findings coincide with reality only if the workers use PPE for hearing in the same way, working hard to implement in reality. We must also consider the usage time dell'otoprotettore relation to the timing of exposure to noise: in fact, a PPE can attenuate 30 dB when worn all day, loses the equivalent of 7 dB if you have not worn for a minutes of exposure time, but if you wear only half of workday provides effective protection of only 3 dB.
PPE for hearing (ear, ear headband, earplug, etc..), Despite the apparent ease of use, ability to have different protection depending on how they are worn.
The technical reference on the subject is represented by the UNI 9432 'Determination of the level of personal exposure to noise at work'.
Let's say in a stage are operated at the same time one or more grinders and machinists, electricians, toolmakers and engineers (not to be present simultaneously in all these departments to have a significant noise hazard) are running assembly or disassembly.
The noise made by a grinder is already just above the upper limit of 80dB (A) rapprenta the exposure limit value, in fact, let's see what he says the technical details of a grinder cumunissima:
For those who make use of the grinder industry, should also protect your hearing: the sound of the machine in action, may in the long run, bring injury to the ear ...
As we can easily deduce the noise of the grinder would add up to the sound of another possible grinder and maybe add up to the sound of a tow used by electricians to join a Trus aluminum while drivers smartellano con i loro preziosi martelli fiorentini e fonici ed attrezzisti urlano dal palcoscenico ai ballatoi per farsi sentire. Proviamo ad immaginare quanti Db sono presenti in quel momento in palcoscenico! sicuramente è auspicabile fare un'adeguata valutazione e decidere di arginare il problema o strutturalmente o a livello organizzativo evitando così la possibilità che vengano causati seri danni all'udito dei lavoratori presenti.
Un approfondimento interessante che riguarda soprattutto gli elettricisti che uniscono o dividono le Trus di alluminio è rappresentato dalla pressione acustica di picco e cioè tutti quei rumori improvvisi che colgono l’operatore impreparato ed
indifeso. Esiste un meccanismo naturale di difesa che è chiamato riflesso tympani.
Two small muscles acting on the chain of ossicles contract by way of reflection when the ear is subjected to sound having intensity of at least 70-80 dB (A) above the hearing threshold.
The tightening of these muscles leads to increased resistance from the eardrum-ossicular system for the transmission of sound, attenuation and therefore
thereby protecting the receptor from the snail sounds too intense.
Note that between the beginning of the stimulus and the beginning of the reflex contraction, there is a delay of at least 90-100 ms:
this means that the tympanic reflex is unable to provide any protection against noise-type pulses are very short and very intense, as
firing of a gun or (in our case) a hammer on a metal surface. It 'should therefore use its IPR.
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