R&B Industrial Ltd were commissioned to test the ventilation systems in a waste water treatment works in South Wales.
We duly carried out the testing and compared the findings with the original design data provided when the building was first put into service, more than 20 years previous.
The site is unusual for a treatment works because virtually the whole site is underground. The original concept was to put a roof over the treatment works and back fill with topsoil to provide a ‘no nuisance’ type of works. This necessitated a robust odour control system which principally keeps the building under a slight negative pressure and thus preventing the uncontrolled release of odour to the outside. All the extracted airflow from within the building is scrubbed clean before exhausting to atmosphere.
Our testing revealed only minor deterioration in the performance of the ventilation systems and following discussions with the water board staff, it transpired that the main reason for carrying out the checks was due to reports of high levels of hydrogen sulphide being detected within certain areas of the building.
Following a long warm dry spell (when hydrogen sulphide can evolve quite quickly), the water board supplemented the originally installed ventilation by hiring additional fans and carbon filters to increase the number of air-changes in the problem areas.
R&B Industrial were asked what could be done to resolve the issues. We firstly identified that there were two main areas where the hydrogen sulphide was most prominent. We then looked at how and where the gas was able to escape.
Skip Handling area:
Unlike most waste water treatment works, the covered skips that hold the solids separated from the raw sewage are stored indoors. These are filled via a screw feed and pipework from the centrifuges and then taken off site to be emptied each day. The site manager commented that on a Monday morning when, up to 6 of the skips could be full, the H2S levels could well exceed the workplace exposure limit, preventing operators from going into the area. Often, the roller doors would be left open to naturally ventilate the area which then compromised the negative pressurisation of the building and allowed nuisance odours to escape.
We quickly identified that the breather ports on the skips were allowing an uncontrolled release of H2S gas into the area and that general ventilation was not the most appropriate engineered control of the hazard.
We then decided that the best approach was to capture the gas release at the source by fitting small hoods over the breather ports which then exchausted the gas stream into the scrubbing system. We used the same principles as we do for the Fire Service with the diesel fume extraction system on their fire engines. H2S gas is corrosive to many materials, so we needed to consider this in the selection of the components that made up the Local Exhaust Ventilation system.
Belt thickener area:
Through years of wear, tear and repairs where 10 pieces are taken off and 9 pieces go back on, the belt thickener area was seeing increasing levels of H2S, Applying HSG258 principles, we fitted polycarbonate sheets to the open weld mesh guarding and added flexible PVC curtaining to the existing canopy to make the machine as close to airtight as possible. The ventilation was increased to ensure that any parts of the machine that could not be sealed had an inrush of air from the room.
Since applying Local Exhaust Ventilation methodolgy, the H2S levels within the problem areas has been virtually eliminated to undetectable levels.
RPE is a particular type of personal protective equipment (PPE) designed to protect the wearer from breathing in harmful substances (or from oxygen-deficient atmospheres) when other controls are either not possible or insufficient on their own.
RPE must be both adequate and suitable:
Adequate – It is right for the hazard and reduces exposure to the level required to protect the wearer’s health.
Suitable – It is right for the wearer, task and environment, such that the wearer can work freely and without additional risks due to the RPE.
If you are considering RPE with a tight-fitting facepiece, each wearer should undergo a ‘face fit’ test. People come in different shapes and sizes, so facial differences will mean that one kind of RPE is unlikely to fit all. The differences are even more significant between men, women, and people of different ethnicity. If the RPE does not fit, it will not protect the wearer.
One significant factor is if the wearer has facial hair; this will prevent an effective seal
eusable half mask respirators (either powered or passive), for either dusts, vapours or gases. Quantative face fit testing is required for full face respirators.
We also carry out LEV design and DSEAR risk assessments for Twining’s Tea, Andover.
Diesel Engine Exhaust Emissions Air Quality Monitoring
On the 29th of September 2016, R&B Industrial attended the BOHS London, South and South East Regional Meeting on Diesel Engine Exhaust Emissions (DEEEs). DEEEs are known to be a significant hazard to health in the workplace: the recent ‘Cancer Burden Study’ [include link http://www.hse.gov.uk/cancer/research.htm ] led by Dr Lesley Rushton at Imperial College estimated the number of deaths in the UK from DEEEs to be around 625 per year, roughly 5% of the total for occupational disease. Individuals at particular risk include those who work in the transport, mining and construction industries. Nevertheless, DEEEs are not yet specifically classified as a carcinogen under COSHH, although they are considered carcinogens by the World Health organisation (WHO).
Chemical hazards from DEEEs include elemental carbon (soot), organic carbon (polycyclic aromatic hydrocarbons (PAHs) and aldehydes), carbon monoxide and NOx. PAHs have a recognised biological monitoring guidance value (BMGV), while carbon monoxide and most common aldehydes have Working Exposure Limits (WELs). In general, the main health hazard is thought to be soot (particulate elemental carbon with adsorbed organic carbons and hydrocarbons), as the other substances are normally only present at significantly below the exposure limits. Although the UK does not have an exposure limit for soot, many countries consider a concentration of 100 µg/m3 to be dangerous. It is also sometimes suggested that a carbon dioxide concentration of 1000ppm is indicative of high levels of DEEEs.
Airborne concentrations of soot can be measured either by air monitoring using baked quartz filters, or by instruments such as the MicroAeth® A51 or the FLIR Airtec. Carbon dioxide can also be monitored by real-time instruments. If a comprehensive survey is required, air sampling using sorbent tubes can determine time-average concentrations of most of the other DEEE components, while carbon monoxide and nitrogen dioxide can be monitored in real-time.
R&B Industrial can carry out workplace air quality monitoring for a wide range of hazardous gases, vapours and particulate / dusts, in London, the Sout East and Southern England.
Corrosion and Health Effects of 1-Bromopropane
In early 2016 R&B Industrial were called in to investigate a possible air quality issue at the Heliworks repair facility in Thruxton, Wiltshire. A depth technical knowledge of process chemistry, air quality monitoring and sampling techniques was required to identify issues. Our in house Technical Specialists & Occupational Hygienist investigated the issues as follows:
A recently installed heater was found to be corroding rapidly, and the supplier had suggested that this could be due to dichloromethane vapour from a paint removal tank. Halocarbons, a chemical group which includes dichloromethane, are known to break down at high temperatures, releasing hydrogen halide gases. These gases form acids such as hydrochloric acid when in contact with water, which can react with metals and deposit halide ions such as chloride, which are corrosion promoters. Due to the large amount of powdered rust, it was possible to take a sample of several grammes and send it for analysis. It was found that the rust contained 1.75mol% bromide but only 0.07% chloride, suggesting that a substance other than dichloromethane was causing the problem.
The only significant source of bromide in the Heliworks facility was a vapour degreasing tank which used 1-bromopropane. Air monitoring using sorbent tubes showed that vapour concentrations in the air near the tank were 8ppm dichloromethane and 6ppm 1-bromopropane. The higher potency of the 1-bromopropane with regard to corrosion was thought to be due to the weaker bromine-carbon bond (bond energy 280 kJ/mol) compared with the chlorine-carbon bond (bond energy 330 kJ/mol), which means that it can form acids much more easily.
Further research showed that 1-bromopropane was an irritant and a neurotoxin, as well as a potential carcinogen and reproductive toxin. Some literature claims that loss of feeling in extremities can begin with continued exposure at concentrations as low as 1ppm. In contrast, suppliers of 1-bromopropane-based solvents maintain that concentrations of 100ppm are safe.
As a result of our work, and a possible health issue being identified, Heliworks made the decision to switch to Solvex HD, which contains no 1-brompropane or dichlromethane.
We are also carrying further out investigatory work & testing on the Local Exhaust Ventilation system which is inbuilt into the vapour degreasing tank, to identify the possible cause of the air quality issues.
Seminar Components, Swansea, South Wales
Seminar Components, required a reliable and energy efficient robotic weld fume extraction system. This was to replace an existing fume extract system which had filtration issues and considerable on-going costs. The existing cartridge filters, in the dust collector, were only lasting 3 – 4 months, before blinding, together with significant, ongoing energy / compressed air costs
Our Industrial Ventilation System specification included
- A fan, inverter controlled from ‘system’ demand,
- A dust collector with very high efficiency cartridge filters, with compressed air cleaning system on-demand.
- A very cost effective (calcium carbonate) powder dosing system absorbing VOC’s from weld fume, ensuring long filter life. This also inerts the flammable weld fume.
- A filter / stack emission monitoring system, ensuring satisfactory return-air quality to workplace. Again providing energy savings, with no heat loss to atmosphere.
The installation was completed during (2013) Christmas shutdown, with production ready to run in the 1st week of January 2014, and we received a reference from the customer (listed in our ‘Testimonials’ section).
We have very recently completed some modifications to the system and the customer is looking to upgrade to our patented ‘SMART-AIR’ system next year; this maximises energy savings with precise air-flow and inverter control, increases filter life and compressed air savings.
We provide competitive dust extraction systems, filters and accessories in the South Wales, Swansea, Neath, Brynmill, Port Talbot, Jersey Marine, Clydach areas.
Verdo Renewables, Andover, Hampshire and Grangemouth Scotland
R&B Industrial Ltd have carried out DSEAR risk assessments and hazardous area classifications for Verdo renewables, based in Andover Hampshire and also Grangemouth Scotland. The assessments covered fire and explosions for their wood processing facilities.
Verdo carry out a range of wood chipping treatments in order to produce briquettes and pellets for wood burning bio-fuel industries. A large amount of wood dust is produced from these processes and there are many fire and explosion risks within the facility which required detailed scrutiny and consideration with regards to control and mitigation methods.
Following a visit from a (HSE) process safety expert our reports were reviewed/ overviewed; it was found that there were no further recommendations/ actions required by the DSEAR expert.
A DSEAR Pre-assessment and detailed site survey were carried out. The main risks from a DSEAR and fire safety considerations were:
Wood chippers, hydraulics presses/ oils etc.
Wood chipping conveyors
Storage of chippings, needles, pellets
Wood dust extractors
Wood needle dryers
Various wood cutting/ sawing activities
Part of the basis of safety and risk reduction measures in a plant of this nature include automatic spark detection and deluge systems, greatly reducing the risk of both fire and explosions. The measures employed by Verdo in this respect were generally very effective and thorough, with some relatively minor modifications being recommended.
Following issue of the DSEAR report R&B Industrial quoted for providing various control and process safety solutions this included:
Design, sizing and modelling of explosion venting/ relief systems together with modification to dust extraction and corresponding installation of explosion relief system.
Wood needle/ pellet dryer main gas supply pipework/ valves and corresponding zoning encompassed a number of non-ATEX electrical panels and control gear. This would have been very costly to move. A partial enclosure around pipework and valve with methane VOC monitoring and gas supply auto- shut off enabled the existing non-ATEX electrical equipment to remain and reduce zoning accordingly. This enabled significant cost savings.
Verdo have implemented all of the high priority recommendations, and have been very happy with the high quality of DSEAR reports produced. Gordon Hambleton H&S Manager
We can carry out DSEAR risk assessment and area classification covering the whole of the UK for virtually all industries and processes including sawmills, wood treatment plants etc.
LEV Testing at a fencing company in Cambridgeshire
Huntree Fencing, Huntingdon, Cambridgeshire manufactures a wide range of quality fencing panels and gates etc. A recent HSE visit highlighted the inadequacy of their existing ventilation system LEV testing and controls. R&B Industrial were selected as a P601 P602 accredited LEV testing company. We were able to carry out, LEV Servicing, Personal Air Sampling (PAS), design, manufacture, install LEV hoods, together with other system improvements.
The LEV testing and reports were carried out in a timely manner, to prevent HSE action. Following this, Personal Air Sampling and real time dust monitoring was performed and an LEV initial appraisal provided.
Advice was also given on DSEAR and wood dust explosions with respect to their wood working operations.
A further area of concern was secondary dust exposure created from operators blowing their clothing down using a compressed air line.
Further recommendations were also made to improve the LEV system design and performance, including:
- Addition of Table saw top hood
- Enclosing and improving extraction on band saw, re-saw
- LEV hood design for a X-cut saw
Addition of a ‘high pressure’ extraction, vacuum point branch. This enables:
- Fine dust to be extracted from the small spigots on the back of hand sanders, routers, morticers etc.
- Floor and crevice tool attachments for vacuuming around machines and floor areas
- A round brush attachment can be supplied/fitted enabling the vacuuming of clothing. This prevents secondary dust release that is created by using compressed air to blow dust of clothing.
Paul Gibson works manager stated ‘We are happy with the work R&B Industrial carried out, their advice and methods of achieving satisfactory (COSHH) control.
R&B industrial are regularly in the in the Cambridgeshire, Nottinghamshire, Lincolnshire, Essex, London areas to carry out:
LEV INITIAL APPRAISALS TESTING and SERVICING TO P601
PERSONAL AIR SAMPLING and REAL-TIME AIR QUALITY MONITORING
COMPLETE LEV SYSTEM DESIGN TO P602 and HSG258, TOGETHER WITH FURTHER CIBSE GUIDELINES.
WE HAVE A PATENTED (‘SMART-AIR’) ENERGY SAVING INVERTER, AIR FLOW CONTROL SYSTEM, SPECIFIC FOR DUST and FUME EXTRACTION SYSTEMS. THIS PROVIDES THE MOST ENERGY EFFICIENT INDUSTRIAL VENTILATION SYSTEM ON THE MARKET TODAY.
Eco Sustainable Dorset
Eco sustainable, approached R&B Industrial for a solution to remove / separate light plastic waste material from their composting / processing site in Bournemouth, Dorset. We proposed an energy efficient, turnkey solution, consisting of:
- Design a series of separator / extract hoods across conveyor / grading screens, providing very specific capture velocities to separate the light plastic waste from other compost material. It was crucial to maintain a constant capture velocity across the 2.0m wide separator screen; this was achieved by creating a ‘plenum-effect’ within the ‘pick-up’ hoods.
- Design of Duct conveying system ensuring correct transport velocities, and minimal system resistance / pressure drops
- Design, manufacture and installation of cyclone separator with drop-out chamber and rotary valve, discharging waste plastic material into skip underside. Modelling of the cyclone air-flow characteristics was carried out to ensure an efficient cyclone (cut-off frequency approx 40micron) with medium pressure drop, ensuring all the light plastic product was discharged through the drop-out chamber and rotary valve.
- Design manufacture and installation of fan loading box / chamber,22 Kw fan, fitted to clean air, exhaust side of cyclone, and complete control panel, including energy efficient variable speed drive, and all associated controls.
- The inverter drive enables fine tuning of the air-flow / capture velocities to pick up more / less product with different grades / types of compost.
Similar cyclone separation systems previously installed onsite have a number of disadvantages compared to the R&B Industrial ‘new style design’:
- They are energy inefficient as the fan is fitted on the air inlet of the cyclone, with the product passing through the fan. A comparable system being fitted with a 45 Kw fan / motor.
- The fans can be prone to damaged impellors, running out-of-balance, and greater noise.
- Shorter fan life-span, as the compost has high ammonia / nitrous oxide concentrations which rot the internals of ducting / fans etc. very quickly.
With a run time of approximately 8 hours / 5 day week the energy savings equate to approx £4,000 pa. Providing a system payback of less than 2 years, compared to the previous style of separator system design
River Woodwork Stack Monitoring
R&B Industrial were contacted by Riverwood work, London, regarding issues with odours and VOCs being emitted from there solvent paint spray booth, stack. The company had received a number of complaints from local residents regarding the odours.
The company had obtained a number of very expensive quotes looking at abatement / carbon filtration for their spray booth discharge.
The paint spray booth ‘stack’ design was very poor with horizontal discharge. R&B industrial carried out VOC / stack emission monitoring and proved that the emission levels were well below Process Guidance note limits, so ideally no further odour control / filtration was required.
The problem was caused by the poor / horizontal stack discharge design. R&B Industrial were able to redesign the stack with vertical discharge and increase stack efflux velocity, whilst keeping within the existing fan performance, i.e. not increasing overall system resistance.
Further stack, structural support complications had to be overcome due to a (transport for London) railway bridge, which was beside the stack location; no support from the bridge could be made, i.e. All structural supports for the spray booth, stack discharge had to be from the ground.
With the increase in efflux / exit velocity, there was a substantial increase in the effective ‘plume’ height, providing excellent dispersal of any odours.
The new ‘stack’ design has now been in operation for approx 8 months, with no further complaints from residents.
Lionel Hitchen Essential Oils
R&B Industrial recently won a 40K contract to carry out a ventilation system specification, design, manufacture, install and commission, at specialist food spice producer, Lionel Hitchen, near Winchester, Hampshire. The inverter controlled, energy saving system comprised:
- Design and manufacture of a heating and cooling Air Handling Unit (AHU), to maintain a constant 16 deg C in the food processing area with a 70% heat recovery / exchange unit, maximising heating / cooling energy savings.
- The AHU was integrated with local exhaust ventilation (LEV), extracting at source from ovens, weigh booths and various process mixers. The primary function of the LEV is to remove spice and garlic odours, via a range of flexible arms and extract booths. The extracted air is filtered via pre and rigid bag filters and odours adsorbed by carbon filtration prior to passing through the AHU, for heat recovery.
- The supply and extract fans are inverter driven with feedback and ratio control from various pressure sensors and internal control algorithms. This maximises energy savings, and optimises system performance and temperature control.
- Within the food processing areas all ducting, booths, canopies etc. are stainless steel
The complete ventilation, AHU and energy saving control system was designed and manufactured within our manufacturing facility and installed with our own in-house Engineers.
The filtration LEV, AHU and odour control system was commissioned by our P601 / P602 ventilation and refrigeration, qualified engineers.
R&B Industrial Ltd have recently installed a complete factory wide energy saving ATEX dust extraction system for the Metal Improvement Co., Curtis Wright, Newbury, Berkshire. The system has replaced a number of smaller individual dust collectors, many not ATEX compliant, extracting from a range of shot blast and shot peening machines.
The new centralised, ATEX dust extraction system is extremely energy efficient being controlled by an inverter controlled fan and automated dampers. The complete system has been designed and manufactured by R&B Industrial Ltd.
Each shot blast / peening machine extract duct is fitted with an actuated damper operated automatically from the machine operation. Air flow sensors detect the dampers opening / closing and automatically adjusts the inverter speed ensuring optimum airflow is always maintained and maximising energy savings.
A number of existing large dust extractors were upgraded to meet full ATEX compliance, including, Design, specification and installation of:
- ATEX explosion relief / burst panels, complete with break / isolation systems wiring
- Explosion backdraught dampers
- Structural calculations
- Upgrading an existing bag house collector with antistatic dust, cartridge filters (pleated bag filters), providing a 40% increase in air-flow
- Earth bonding and various electrostatic control measures
- Temperature detectors, activating water deluge/ spray systems within the dust collector hoppers, to prevent hot embers/ sparks igniting ferrous dust
It is anticipated the new ATEX dust extraction system, with two 30Kw fan sets, will save over £16,000 pa compared with an extractor running full speed, without automated control dampers.
We are continually developing/innovating our products and services range, please see our news page.
We carry out project and ventilation works in the following areas: Hampshire, Berkshire, Avonmouth, Dorset, Cornwall, Devon, Wiltshire, Exeter, Somerset, Oxfordshire, Bristol, Buckinghamshire, Middlesex, Northamptonshire, Surrey, Sussex, Wales, Bedfordshire, Gwent, Cambridgeshire, Cardiff, Carmarthenshire, Ceredigion, Clackmannanshire, Derbyshire, Essex, Gloucestershire, Greater London, Gwynedd, Taunton, Hertfordshire, Isle of Wight, Nottinghamshire, Kent, Leicestershire.