Navigating the Risks of Metal Powders in Selective Laser Sintering (SLS) Printing

We have supported metal Additive Manufacture safety since its very early days in the 2010’s and worked extensively with the UK’s largest installed base of 3D printers for a major Blue Chip company.  We worked onsite multiple days per week for over 6 years for this business to drive safety systems and have detailed knowledge of all aspects of 3D metal additive from biological and air monitoring through to the ATEX and DSEAR requirements in print, depowdering and post processing.  If you need support on safety in additive manufacturing, please contact Roger Hart directly.

Selective Laser Sintering (SLS) is a cutting-edge 3D printing technology that uses a laser to sinter powdered materials, creating complex and high-strength parts. However, when using metal powders in SLS printing, there are significant dangers that must be managed to ensure safe operations. Here are the key risks associated with metal powders in SLS printing and how to mitigate them:

1. Fire and Explosion Hazards of Metal Powders

Metal powders like aluminium, titanium, and steel are highly flammable and can pose severe fire and explosion risks. These powders can ignite easily when exposed to sparks, open flames, or even static electricity.

Mitigation Strategies:

• Proper Ventilation: Ensure the printing area is well-ventilated to prevent the accumulation of combustible dust.
• Static Control: Implement anti-static measures, such as grounding and using anti-static mats and clothing.
• Controlled Environment: Use inert gas atmospheres, like argon or nitrogen, to reduce the risk of ignition during the printing process.

2. Health Risks from Inhalation

Inhalation of metal powder particles can lead to serious health issues, including respiratory problems, lung diseases, and metal poisoning. The fine particles can become airborne during handling, posing an inhalation hazard.

Mitigation Strategies:

• Personal Protective Equipment (PPE): Workers should wear appropriate PPE, including respirators, gloves, and protective clothing.
• Dust Collection Systems: Install dust collection and filtration systems to capture airborne particles at the source.
• Proper Training: Ensure all personnel are trained in safe handling procedures and the use of PPE.

3. Chemical Reactions and Toxicity

Some metal powders can react with moisture or other chemicals, leading to the release of toxic gases. For example, titanium and aluminium powders can react with water to produce hydrogen gas, which is highly flammable.

Mitigation Strategies:

• Humidity Control: Maintain a low-humidity environment to prevent moisture from interacting with metal powders.
• Chemical Storage: Store metal powders in airtight, moisture-free containers and keep them away from incompatible substances.

4. Environmental Contamination

Improper disposal of metal powders can lead to environmental contamination, affecting soil and water quality. Metal powders must be handled and disposed of in accordance with environmental regulations.

Mitigation Strategies:

• Waste Management: Implement proper waste disposal protocols for metal powders and used containers.
• Environmental Monitoring: Regularly monitor the environment around the printing facility for signs of contamination.

5. Mechanical Risks

Handling and processing metal powders can pose mechanical risks, such as cuts, abrasions, and injuries from heavy equipment. These powders can also cause machinery to wear out more quickly, leading to mechanical failures.

Mitigation Strategies:

• Safety Protocols: Develop and enforce strict safety protocols for handling equipment and materials.
• Regular Maintenance: Perform regular maintenance and inspections on all equipment used in the SLS printing process to ensure safe operation.

Conclusion

While SLS printing with metal powders offers numerous advantages in terms of manufacturing flexibility and material properties, it also comes with significant risks. Fire and explosion hazards, health risks from inhalation, chemical reactions, environmental contamination, and mechanical risks all need to be carefully managed. By implementing proper safety measures, providing adequate training, and adhering to regulatory guidelines, businesses can harness the power of SLS printing while ensuring the safety of their employees and the environment. Prioritising safety not only protects people and property but also enhances the overall efficiency and reliability of the SLS printing process.

When it comes to emergency lighting, understanding the difference between maintained and non-maintained systems is crucial for ensuring safety and compliance. Here’s a breakdown to help you decide which type is best for your building.

Maintained Emergency Lighting

Maintained emergency lights are designed to be on at all times. These lights are integrated into the regular lighting system and remain illuminated during normal operation. In the event of a power failure, they continue to provide light, powered by a backup battery. This type of lighting is commonly used in public venues such as cinemas, theatres, and shopping centres, where the lights need to be visible even when the main lighting is dimmed.

Key Features:

• Always on, even during normal operation.
• Provides continuous illumination during power failures.
• Ideal for public spaces where lighting is often dimmed.

Non-Maintained Emergency Lighting

Non-maintained emergency lights, on the other hand, are designed to activate only when the main power supply fails. These lights are powered by a battery that is kept charged by a trickle of mains power. They are typically used in workplaces, offices, and schools, where the building is usually well-lit during occupancy.

Key Features:

• Activates only during power failures.
• Battery-powered with a trickle charge from mains power.
• Suitable for workplaces and buildings with consistent lighting.

Dual-Mode Emergency Lighting

Some emergency light fittings can operate in both maintained and non-maintained modes. These switchable units offer flexibility, allowing a single type of light to be used in various settings. This is particularly useful for buildings with multiple uses, ensuring compliance with safety regulations without the need for different types of lighting.

Making the Right Choice

Choosing between maintained and non-maintained emergency lighting depends on the specific needs of your building and its occupants. Conducting a fire risk assessment with a competent person can help determine the most suitable option. This assessment will ensure that your emergency lighting system meets current regulations and provides adequate safety for all occupants.

By understanding the differences and applications of maintained and non-maintained emergency lighting, you can make an informed decision that enhances safety and compliance in your building.

Emergency lighting is crucial for ensuring the safety of building occupants during power failures or emergencies, regular testing and maintenance of these systems are essential to ensure they function correctly when needed.

Legal Requirements

In the UK, it is a legal requirement under both Building Regulations and the Regulatory Reform (Fire Safety) Order 2005 for all business premises to have emergency escape lighting. This includes offices, factories, schools, hospitals, and entertainment venues.

Testing Frequency

The frequency of testing emergency lighting can vary depending on the type of system, but general guidelines include:

• Monthly Tests: Known as “flick tests,” these are short functional tests that simulate a mains power failure to ensure the emergency lights switch on and illuminate correctly. These tests should be conducted using a secure device key, often referred to as a fish key, rather than switching off the mains power, which could be hazardous.
• Annual Tests: A full-duration test should be conducted annually, where the primary lighting circuit is switched off, and the emergency lights are left on for three hours. This ensures the system can sustain illumination for the required duration in an actual emergency.

Record Keeping

It is important to keep a record of all tests, including any faults found and the remedial actions taken. This helps ensure that the emergency lighting system remains reliable and effective.

Competent Personnel

All tests should be carried out by a competent person due to the critical nature of the system in ensuring occupant safety.

By adhering to these guidelines, businesses can ensure their emergency lighting systems are always ready to provide safe evacuation routes during emergencies.

Refreshed asbestos guidance published

Working with a wide range of clients in diverse sectors we often come across sites which are remote, small or perhaps a site within a site.  When you have one of these locations you’re typically responsible for everything within your demise including fire extinguishers.

The challenge is on value.  When you arrange your service for a larger office having a fire engineer visit and complete a review of all types of extinguishers is fairly typical and often reasonable value.  Having the same person visit a site some distance from other locations to service just a few extinguishers can be prohibitively expensive but you still have your duty under the law to ensure adequate fire precautions are in place.

But, there is a potential solution in the form of composite P50 extinguishers.  These do cost a little more than the traditional alternative but you might find that over their 10-year working life you could save a significant amount of money.  The caveat is that you might need a CO2 type which is not available currently, but if you don’t you might want to consider this alternative.

Here’s a link to a provider to give more information on cost and lifetime cost of these types and where they might be suitable for use.  We have no affiliation with the provider but hope you can perhaps make a saving: https://www.safelincs.co.uk/how-are-p50-fire-extinguishers-different/

We have helped our clients with exposure to wood dust for over 30 years.  We completed our first air monitoring in the early 1990s and are perfectly placed to support and advise you on wood dust exposure.  We also work together with leading Local Exhaust Ventilation Engineers to support our clients in implementing cost-effective and suitable extraction systems to help control wood dust exposure within all types of industries.

It is worth noting that the acceptable exposure levels for wood dust exposure have reduced significantly in recent years.  For a very long time, an exposure of 5 milligrams per cubic metre would have been seen as acceptable, since 2020 this has reduced to just 2 mg/m3 and may fall further.  See our earlier blog post from January 2018 for more information on these changes.

All of the above leads us onto some recent prosecutions for two companies which exceeded the allowable wood dust exposure limit, read on to find out more about what happened and contact us or ask one of our experts to call you back if you need further support.  If you’re a member of our Safety~net support service then please get in touch, if you would like to become a member then please let us know.

A Norfolk woodworking company has been fined £25,000 for failing to control its employees’ exposure to wood dust.

A Health and Safety Executive (HSE) inspection of The Joinery Yard Limited at Sweet Briar Road industrial estate, Norwich in November 2019 identified failings in the company’s control measures to prevent exposure of their employees to wood dust. As a result, enforcement action was taken.

Wood dust is a respiratory sensitiser that can cause long term health effects including occupational asthma.

A subsequent inspection in July 2022 showed that the company had failed to maintain standards and enforcement action was taken again. This inspection identified ongoing failings in the company’s control measures and found that they had failed to take appropriate precautions to ensure the safety of workers exposed to wood dust.

HSE has guidance on working in the woodworking industry and is running the Dust Kills: Wood Dust campaign page.

At a hearing at Norwich Magistrates’ Court on 4 October, The Joinery Yard Ltd of Aylsham Road, Norwich, Norfolk pleaded guilty to breaching the Health and Safety at Work Act 1974, Section 2 (1). They were fined £25,000 and ordered to pay costs of £2681.77.

After the hearing, HSE Inspector Natalie Prince said “The fine imposed on The Joinery Yard Limited should underline to everyone in the woodworking industry that the courts, and HSE, take a failure to follow the regulations extremely seriously.

“Wood dust can cause serious health problems and all businesses need to protect their workers’ respiratory health.

“We will not hesitate to take action against companies which do not do all that they should to keep people safe.”

This HSE prosecution was supported by HSE enforcement lawyer Sam Crockett and paralegal officer Rebecca Forman.

A Northwich furniture company has been fined £16,000 after it repeatedly failed to protect its employees from exposure to wood dust.

Pineland Furniture Ltd, based on Witton Street in the Cheshire town, was inspected by the Health and Safety Executive (HSE) on two separate occasions over a two-year period – with both identifying identical breaches.

Nathan Cook, HSE senior enforcement lawyer, told Chester Magistrates Court, how a visit in December 2019 found significant breaches of the Control of Substances Hazardous to Health Regulations 2002 (COSHH) – resulting in six improvement notices being served. These included requirements for the company to undertake statutory examinations of its wood dust extraction systems and to undertake face fit testing for those employees required to wear tight fitting face masks.

However, another visit to the same premises in November 2021 found identical breaches and again improvement notices were served.

This inspection came as part of HSE’s national campaign targeting woodworking businesses. The significant occupational health risks associated with wood dust and the continued failure to ensure control of exposure to wood dust resulted in HSE prosecuting the company.

Pineland Furniture Limited pleaded guilty to breaching regulations 7(1) and 9(2)(a) of COSHH. They were fined £16,000 and was ordered to pay £3008 costs at a hearing at Chester Magistrates Court on 11^th October 2023.

After the hearing, HSE inspector Ian Betley said: “Wood dust is a substance hazardous to health because it can cause serious non-reversible health problems, including asthma; dermatitis; and irritation to the eyes, nose and throat.

“Occupational lung disease causes the death of 12,000 people in Great Britain annually, and there are an estimated 19,000 new cases of breathing and lung problems each year, where individuals regarded their condition as being caused or made worse by work.

“It is important to carry out statutory thorough examinations of extraction equipment and ensure face fit testing, as required by COSHH to help prevent ill health.

“We will not hesitate to take enforcement action when necessary to make sure workers’ health is protected.”

All staff who work in construction must have access to adequate welfare facilities.  This means toilets and facilities to wash, change, eat and rest. The guidance below applies to contractors but this also applies to those clients who are hosting contractors to perform work on their sites.  As the client you must also help to ensure that the arrangements made by your contractors are adequate and decisions on this need to be taken at the planning stage of the project.  Naturally, there will be some variation in what is considered reasonable when you have low numbers of staff and short-duration projects. If you have questions or are already (or wish to become) a member of our Safety~net competent person scheme you can call and speak to any of us for some specific help, guidance and support.  Read on for some simple guidance on what is required and see the bottom of the post for some more links to useful guidance.

Who does this apply to?

Contractors are required to provide welfare facilities and clients must ensure this happens. Decisions and action on this need to be taken at an early stage of project planning.

• Commercial clients – you must make sure contractors have arrangements for providing the right welfare. This applies to all construction work.
• Contractors – you must provide the right welfare for workers under your control while they are on site. Principal Contractors must ensure that this is done from the start of the project until it finishes.

Clients should co-operate with contractors and help them in situations where providing welfare facilities are difficult.

What does good look like?

Schedule 2 of the Construction (Design and Management) Regulations 2015 (CDM 2015) lists the welfare facilities that should be in place at any site. This includes:

• toilets and washing
• changing, eating and rest areas

The type and number of facilities you need depends on the size and type of work. You may need additional facilities (such as showers) to control the risks from hazardous substances like cement, lead or micro-organisms. Also, remember that separate facilities may be needed for men and women.

Where should facilities be positioned?

Consider the positioning of your facilities before starting on site. This will depend on the work you are doing. For fixed sites think about:

• whether they will have to be moved during the project
• access for cleaning and maintenance
• encouraging the use of washing facilities by positioning them near to rest / eating areas
• the distance from the furthest part of the site to the nearest facilities and how long it takes someone to get there (either walking or by vehicle). This time should be as short as possible. You may need additional toilets and washing facilities for workers in more remote parts of larger sites
• arrangements for using any existing facilities. You can use those in a local café, public toilets or an occupied building. However, you need to make sure:
  • you have proper agreement with the owner allowing their use (not necessarily in writing)
  • they are available all the time that workers are on site
  • there are measures for keeping them clean and replacing towels, soap, toilet paper etc

Temporary sites, like highway utility or repair work, and workers in remote areas, such as fields, require good welfare too.  Where you put your welfare for this type of work depends on a number of factors such as how long the work will take, the distance from other available facilities and whether there will be any hazardous substances present. Options include:

• Central compound – workers should be able to access this easily and quickly. Take into account any likely delays due to traffic / distance. You may need ‘satellite’ compounds for more remote workers.
• Mobile units – a number of different self-contained welfare units are available. Remember when selecting these that they still have to meet certain minimum standards regarding toilets / washing and changing, eating and rest areas.

Welfare: Further Guidance

Construction – Welfare standards – This guidance sets out the approach Inspectors and Visiting Officers take when inspecting issues related to welfare on construction sites.  Detailing interpretation of the requirements of Schedule 2 of CDM

Managing construction health risks: Welfare

L24, Workplace health, safety and welfare, approved code of practice and guidance

L153, Managing health and safety in construction.

The Construction (Design and Management) Regulations 2015 SCHEDULE 2 Minimum welfare facilities required for construction sites

HSE has updated its welfare guidance – Construction welfare standards (hse.gov.uk)

• Distances are now given for toilet proximity which should prevent people having to drive for miles to use the bathroom – any worker should be within 150m of a toilet on site.
• For roadworkers they may have to drive to a welfare hub, however the time taken to drive should be the same that it takes to walk 150m, so if it takes 2mins to walk that distance then any drive should not take more than 2mins under normal conditions.
• For larger sites satellite toilets may be needed.
• The ratios for toilets per person have changed due to the British Standard being updated – it used to be 1 toilet for 7 people, now it’s 1 for 5 people.
• Clear consideration is given to the provision of sanitary waste disposal facilities – HSE will be making the provision of sanitary waste disposal facilities a point to assess.  With the changing face of a more inclusive industry, suitable provision must be made for female workers on site.  This is nothing new but it has been overlooked by contractors for years.
• Use of public conveniences and cafes should be a last resort – with proper planning (as required by CDM) welfare should be available during the entire project.
• HSE will be checking welfare on all sites.  For larger projects HSE will be tracking back to Clients to determine where the failings have occurred and enforce at that point.

The Health and Safety Executive has recently published updated guidance for staff working from home.  With a significant number of staff remaining on a hybrid working arrangement, it’s worth relooking at your arrangements for assessing safety of these staff.

Don’t forget that you retain a responsibility (duty of care) for these workers and this crosses over into their wellbeing as well as their health and safety  – particularly where they’re working from home for several days per week.

You can use self-assessment forms to help you in this and for members of our Safety~net competent person support scheme we can provide resources which can help you assess this or perform a session to help staff complete these.  We can even visit or perform remote assessments if that is something you require.  If you are using self-assessment forms we would suggest that you also request a photograph of the working space to enable you to support your assessment of the self-assessment with suitable information.  Remember, younger staff can often be in flatshares or bedrooms which can make maintaining a suitable working environment challenging.

Contact us for more advice or join our competent person scheme to get the support you need.  Below is further information from the updated guidance which is worth a review.

HSE: working from home guidance and resources

Starting in October 2023 and continuing until March 2024, HSE will begin a series of workplace inspections to review exposure to metalworking fluids (MWF).  Those clients operating CNC machinery should review their current processes to ensure that they align with best practices including LEV design and annual inspections, regular metal working fluid quality checks and regular occupational health checks for lung and skin conditions.

If you are a retained client we can assist you to make sure your arrangements for metalworking fluids are robust, please get in touch with your consultant or request a call back to set a date.  If you are not currently a member then please see details of our competent person support service here

Below is the original release from the Health and Safety Executive:

Metalworking inspections start in October

From October until March 2024, HSE will be inspecting manufacturing businesses that use metalworking fluids or coolants in their machining processes.

Inspectors will be focused on how employers are ensuring workers are protected from exposure to fluid or mist generated by computer numerical control (CNC) machines and that regular health checks are in place.

There are 3 areas where manufacturing companies, particularly smaller companies, commonly fall down on compliance:

• not having Local Exhaust Ventilation (LEV)
• not completing regular fluid quality checks
• not providing regular health checks for lung and skin conditions.

Be prepared for inspection

Metalworking fluid is a hazardous substance that comes under COSHH regulations (Control of Substances Hazardous to Health Regulations 2002).

Exposure to metalworking fluids can cause harm to lungs and skin through inhalation or direct contact with unprotected skin; particularly hands, forearms and face. Breathing in the mist generated by machining can lead to lung diseases such as occupational asthma and occupational hypersensitivity pneumonitis.

To reduce exposure, you need control measures in place. LEV should be fitted on CNC machines to carry away any harmful metalworking fluid mist, which is difficult to see in normal lighting.

Fluid quality should be regularly checked, focusing on concentration, pH, bacteria and contaminants. Fluid systems can become highly contaminated with harmful bacteria.

Where there is exposure to fluid or mist, it is a legal requirement to carry out health surveillance even when preventative controls are in place. You will need to involve an occupational health professional and workers should be encouraged to report any health symptoms that occur.

Find out more

See our campaign website for more details including:

• Guidance on buying and using local exhaust ventilation
• Machining with metalworking fluids information sheet
• How to look after your metalworking fluid
• Setting up occupational health and health surveillance.