Ethentic Ethentic Higher Safety Higher Safety Chipmunk Data Chipmunk Data
  • Higher Safety Higher Safety Chipmunk Data Chipmunk Data Ethentic Ethentic

    ON-TOOL CONTROLS ESSENTIAL TO MINIMISE SILICA EXPOSURE

    Research supports tough HSE enforcement line on control of respirable dust 

    Many construction activities such as grinding, finishing, polishing, mortar removal, sanding and cutting produce large quantities of dust including materials containing silica and gypsum in the inhalable and respirable size fractions and if uncontrolled can cause exposure exceeding UK occupational exposure limits.

    HSE has now published Research Report RR926 – On-tool controls to reduce exposure to respirable dusts in the construction industry – A review which reports findings that both on-tool local exhaust ventilation and water suppression is capable of effectiing exposure reductions of greater than 90%.

    Where the two on-tool methods were directly compared there was often no significant difference in control effectiveness.

    The objective of this project was to conduct a review of the literature on the subject of the effectiveness of on-tool controls and to summarise this information for HSE.  The Executive Summary is reproduced below.

     

    EXECUTIVE SUMMARY

    Objectives

    Many processes in the construction industry create large quantities of dust; often materials used in construction contain silica. If the dust emissions from these processes are not controlled they can cause exposures that exceed UK occupational exposure limits and consequently lead to occupational diseases such as cancer, silicosis, chronic obstructive pulmonary disease and asthma. A common way to control these hazards is to apply local exhaust ventilation (LEV) however, construction sites tend be temporary workplaces, which makes the application of traditional LEV difficult. One solution is to affix LEV to the tool being used or to use another mobile form of on-tool control such as water suppression.

    Much of the information held by HSE on on-tool controls requires updating and there has been much research carried out in the field in recent years. The objective of this project was to conduct a review of the literature on the subject of the effectiveness of on-tool controls and to summarise this information for HSE.

    Main Findings

    On-tool LEV is capable of reducing exposures created by processes such as; tuck-point grinding to remove mortar, surface grinding, finishing and polishing, block, slab, brick and tile cutting, floor and drywall sanding. In most cases exposure reductions of greater than 90 % were achieved, sometimes after modifications to the LEV hood. Water suppression was found to be an effective on-tool control for reducing exposure to respirable dusts. Where the two on-tool control methods were compared no significant differences were found.

    The volume flow rate of air for good on-tool control required is typically 50 m3h-1 as a minimum but ideally 80 – 130 m3h-1 is recommended. The choice of vacuum source is vital; typically industrial vacuum cleaners are used, which tend to recirculate air back into the workplace. It is important that they have a final filter with a filtration efficiency of at least 99 % to prevent reintroducing captured respirable dusts back into the workplace air. To this end vacuum cleaners with cyclone type pre-filters are desirable or a vacuum fitted with an automatic back flush system to maintain adequate volume flow rates. Where dusts containing crystalline silica are produced a minimum of a Class M vacuum cleaner with final filter efficiency greater than 99.9 % should be used. When using water suppression, the importance of the volume flow rate of water was not widely agreed upon. Although where it was considered a flow rate 0.5 lmin-1 was considered to be a minimum.

    Even with exposure reductions of 90 % and greater, on-tool controls never completely eliminated exposure and could not always reduce it to below occupational exposure limits, especially where materials contained silica. This may mean that the use of supplementary respiratory protective equipment (RPE) is required. It should be noted however that most of the studies reviewed measured task-based exposure and not whole shift exposure and that 8-hour time weighted average (TWA) exposures may be lower, especially where workers perform different tasks throughout the day.

    The use of on-tool controls was not without issue. Many workers commented that the addition of extraction hoses or the need to carry or move water tanks made the tools ergonomically difficult to use and adversely affected their productivity. Some field studies noted that as operators became more familiar with new tools the effectiveness of the controls improved. This shows that where new tools and controls are to be applied training will be an important part of achieving good control.

    An internet search was conducted to determine the types and availability of on-tool extraction devices. A wide range of power tools fitted with extraction and dust control devices were available for purchase or hire either direct from manufacturers or from retailers and hire companies. Most companies offering extracted tools also offered vacuum cleaners/extraction units; most were of unspecified dust class. Vacuum cleaner manufacturers tended to be those who specify the dust class. L and M class vacuum cleaners were widely available, H class vacuum cleaners were only available from a limited number of suppliers.

    Latest Construction Health and Safety News

    WORKMAN FELL FROM UNSECURED LADDER

    Industrial cladding company failed to assess and control WAH

    Read the rest of this article »

    Posted on 18th January 2019

    SCAFFOLDER FELL THROUGH FRAGILE ROOFLIGHT

    Fall through roof leaves workman with life-changing injuries

    Read the rest of this article »

    Posted on 18th January 2019

    ARM DRAGGED INTO CONVEYOR BELT DANGER

    Workman seriously injured on first day at work in quarry

    Read the rest of this article »

    Posted on 16th January 2019

    ROOF TRUSSES TOPPLED TRAPPING WORKMAN

    Principal contractor failed to plan, manage and monitor project

    Read the rest of this article »

    Posted on 16th January 2019

    SCAFFOLDING AWARENESS TRAINING FOR ALL

    CISRS set to target painters, bricklayers, electricians and plumbers

    Read the rest of this article »

    Posted on 16th January 2019

    HSE ENFORCEMENT DATABASE REMAINS OFFLINE

    hselogo1Access to HSE prosecutions and notices register mysteriously unavailable

    Read the rest of this article »

    Posted on 15th January 2019

    POOR LIFT MAINTENANCE CLAIMED LIFE OF CHILD

    Affordable housing business and contractor fined over £1.5m

    Read the rest of this article »

    Posted on 15th January 2019

    NEW CPA CRANE SAFETY GUIDANCE ISSUED

    Guide covers use of mobile lifting appliances beside railways

    Read the rest of this article »

    Posted on 14th January 2019

    RIBA CONDEMNS RISKIER PROCUREMENT OUTCOMES

    Holistic focus on safety is required and not just cost cutting

    Read the rest of this article »

    Posted on 8th January 2019

    DIRECTOR JAILED OVER PAINT STRIPPER ILLEGAL SALE

    Banned and restricted chemicals sold contrary to legal requirements

    Read the rest of this article »

    Posted on 5th January 2019

    CLIENT FAILED TO PROCURE ASBESTOS SURVEY

    Demolition work released large quantities of asbestos fibres

    Read the rest of this article »

    Posted on 2nd January 2019

    LIVE WORKING IGNITED CLOTHES OF ELECTRICIAN

    Spanner came into contact with live terminal causing life-changing burns

    Read the rest of this article »

    Posted on 31st December 2018

    WORKMEN FELL FROM ‘BIN’ ATTACHED TO EXCAVATOR

    Premature removal of scissor lift prompted unsafe system of work

    Read the rest of this article »

    Posted on 31st December 2018

    MANY SITES FAIL HSE HEALTH RISK CONTROL TEST

    HSE Construction site ‘blitz’ finds breaches at 43% of site visits

    Read the rest of this article »

    Posted on 31st December 2018

    MAKESHIFT FALL ARREST SYSTEM CAUGHT ON CAMERA

    Contactors fined for using harness not attached to suitable anchor

    Read the rest of this article »

    Posted on 31st December 2018

    HYDRAULIC RAM SEVERED HAND OF WORKMAN

    Major contractor failed to follow own policies and procedures

    Read the rest of this article »

    Posted on 31st December 2018

    ALL WORK AREAS NOT INCLUDED IN ASBESTOS SURVEY

    Company fined after asbestos containing materials were released

    Read the rest of this article »

    Posted on 31st December 2018

    FESTIVE GREETINGS TO ALL OUR READERS

    Read the rest of this article »

    Posted on 18th December 2018

    POSITIVE STORY ON FRAGILE SURFACE HAZARDS

    Major roofing contractor testifies to working from below roof

    Read the rest of this article »

    Posted on 18th December 2018

    LEISURE CENTRE USER FELL ILL AFTER SHOWER USE

    Legionella risk assessment and control measures found wanting

    Read the rest of this article »

    Posted on 18th December 2018

    STONE CUTTING MACHINE GUARDS FAILED HSE TEST

    Precautions taken following HSE enforcement fell into disuse

    Read the rest of this article »

    Posted on 18th December 2018

    ROOFWORK CREATED CARBON MONOXIDE RISK

    Falling rubble damaged and blocked home chimney flue

    Read the rest of this article »

    Posted on 18th December 2018

    HSE SAFETY ALERT: TOWER CRANE BRAKES

    Collapse of tower crane jib in high winds prompts HSE warning

    Read the rest of this article »

    Posted on 11th December 2018

    VISITING ENGINEER CRUSHED BY SCAFFOLD TUBES

    Principal contractor “signed off” contractor storage arrangements

    Read the rest of this article »

    Posted on 11th December 2018

    CONCRETE EJECTED BY PUMPING UNIT CLAIMED LIFE

    Company and director failed to train and supervise pumping operations

    Read the rest of this article »

    Posted on 5th December 2018
    Ethentic Ethentic Higher Safety Higher Safety Chipmunk Data Chipmunk Data
  • Higher Safety Higher Safety Chipmunk Data Chipmunk Data Ethentic Ethentic

    2 Responses to “ON-TOOL CONTROLS ESSENTIAL TO MINIMISE SILICA EXPOSURE”

    1. HSE PRIORITIES FOR CONSTRUCTION SECTOR 2013-14 | PP Construction Safety News Desk Says:

      […] control – particularly during roof valley tile cutting and all work with paving and blocks; […]

    2. HSE CONSTRUCTION DUST ‘COORDINATORS’ ON THE ROAD | PP Construction Safety News Desk Says:

      […] The two free half day events and exhibitions are aimed at managers, supervisors and operatives. The aims to raise awareness of the health problems caused by construction dust and the simple controls available. […]