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Ensuring compliant ventilation in Scotland isn’t just about improving air quality: it’s about meeting essential industry and safety standards that protect people, property and the continuity of your business.  At Sigma Engineering, we design, manufacture, and install commercial ventilation systems  across Scotland. We’ve helped businesses in sectors from hospitality to healthcare invest in compliant, efficient systems that meet or exceed relevant standards such as DW/172 and TR19.   In this guide, we’ll explain what these standards are, why they matter for commercial kitchens and other occupational spaces in Scotland, and how our bespoke approach ensures compliance while achieving performance and energy efficiency goals. What Are DW/172 and TR19? To put it simply, DW/172 defines how kitchen extract systems should be designed and installed; TR19 guides how they must be maintained and cleaned to stay safe and compliant over time. DW/172  is the Specification for Kitchen Ventilation Systems  published by the Building Engineering Services Association (BESA), and it has become the authoritative standard in the UK for designing, installing and maintaining commercial kitchen ventilation. It’s widely referenced by designers, contractors and building control professionals because it defines best practice for canopy design, airflow rates, grease management, fire safety and more. While DW/172 isn’t legislation in itself, adherence to it is generally expected where commercial kitchen systems are installed.  TR19 , on the other hand, is the HVCA (Heating and Ventilating Contractors’ Association) Guide to Good Practice  for commercial kitchen extract systems. It focuses on internal cleanliness, accessibility for cleaning, and maintenance procedures that prevent the build-up of grease and contaminants inside ductwork and fans — a significant fire hazard if ignored. Why Compliance Matters for Ventilation Ventilation is a vital part of health and safety in a commercial kitchen. Simply put, it protects people and premises from a range of risks: Health and Safety Commercial kitchens generate heat, steam, odours, smoke, and airborne contaminants (unspent gasses) that must be removed efficiently. Without effective ventilation, staff in a kitchen may be exposed to conditions that compromise their comfort and health.  Proper ventilation also removes combustion by-products from gas appliances, improving safety and working conditions. Preventing Fires Grease accumulation in ductwork and extract canopies is one of the most common causes of kitchen fires. DW/172 outlines design strategies — such as canopy sizing and access for cleaning — that reduce the likelihood of grease build-up, while TR19 ensures that maintenance regimes keep internal system surfaces free of risk. Regulatory and Insurance Compliance Building control officers, insurers, and environmental health inspectors often reference DW/172 and TR19 when assessing compliance. Systems that are well-designed and maintained under these standards are easier to justify during audits or inspections, and they help protect businesses from fines, enforcement notices or insurance issues. Energy Efficiency and Operational Performance Poorly designed ventilation systems can waste energy, drive up utility bills, and struggle to maintain balanced airflow. By designing systems with correct extraction rates, make-up air integration, and modern fan technology, compliance can also deliver better performance and lower on-going costs. How Sigma Engineering Ensures DW172 & TR19 Compliance At Sigma Engineering , we take a holistic approach to ventilation compliance that combines industry expertise with tailored engineering solutions. Bespoke System Design Kitchens vary a great deal in layout, cooking processes, and extract requirements. We begin every project with a detailed survey to understand your operational needs, layout constraints and performance goals. Using this insight, we design bespoke extract canopies, duct systems, fans, and make-up air solutions that are sized and specified to meet DW/172 standards for airflow, canopy coverage , fire rating and access for cleaning — all critical for compliance from day one. Advanced Technology & Components We incorporate high-efficiency fans, energy recovery elements, and precision-engineered ductwork into our systems to achieve efficient performance without compromising compliance. Maintenance Accessibility DW/172 and TR19 both emphasise the importance of accessible internal surfaces for cleaning. We integrate ample access panels and design system layouts that make regular cleaning straightforward. This reduces the risk of grease build-up and ensures that maintenance teams can meet the rigorous cleaning standards set out in TR19. Consulting and Documentation Regulatory compliance often depends on good documentation. As a registered member of BESA, we prepare accredited planning designs, technical drawings and compliance documentation that give confidence to building control officers, planners, and insurers alike. Common Sectors That Benefit from Compliance We support clients across a range of sectors where effective ventilation is critical: Commercial Kitchens and Restaurants  – from casual dining venues to large hospitality operations, where the performance of the extraction system is paramount. Healthcare and Care Homes  – where air quality affects vulnerable occupants. Industrial and Manufacturing Facilities  – controlling fumes, dust and process emissions with Local Exhaust Ventilation (LEV) systems. Public Buildings and Education  – ensuring healthy environments for students and staff. Staying Compliant Over Time Unfortunately, compliance isn’t just a one-off project: it’s an ongoing commitment. At Sigma Engineering, we can assist with maintenance planning and advice, even if we didn’t originally install your system, to help you maintain cleanliness, airflow balance, and performance.

Ventilation is one of those parts of a building that tends to be noticed only when it stops working properly. Poor air quality, lingering odours, excess heat or a build-up of grease can all have a direct impact on people’s comfort and safety.  For many commercial buildings, an extractor fan is essential. But not every site can accommodate traditional ducted extraction. This is where a recirculating extractor fan  may come into the conversation. Understanding what a recirculating extractor fan does, and when it is the right solution, is key to making the right long-term decision for your building. What Is a Recirculating Extractor Fan? A recirculating extractor fan is a ventilation system that filters air before returning it back into the same space, rather than extracting it to the outside. Instead of using ductwork to expel air through an external wall or roof, the system relies on filtration to remove contaminants such as grease, odours, smoke or particulates. The filtered air is then released back into the room. These systems are commonly associated with kitchens, but they are also used in other commercial environments where local air treatment is required. How Recirculating Extractor Fans Work At a basic level, a recirculating extractor fan draws air into the unit using a fan system. That air then passes through a series of filters, which may include: Grease filters Carbon or activated charcoal filters Particulate or specialist filtration depending on the application Each stage is designed to remove specific contaminants. Grease filters trap airborne oils, while carbon filters are used to absorb odours. In more advanced systems, additional filtration may be used to improve indoor air quality. Once filtered, the air is returned to the space. Because the air is not expelled outside, the design and specification of the system become especially important. Poorly designed recirculating systems can struggle with odour control or long-term performance. This is where a design-led approach makes a difference. Recirculating vs Ducted Extraction: What’s the Difference? Traditional ducted extractor systems remove air from a building entirely. They are a great choice if the space, planning and building layout allows it. However, ducted systems are not always feasible. A recirculating extractor fan can be considered when: External duct routes are not possible Planning restrictions limit external alterations Structural constraints make ductwork impractical A temporary or modular solution is required When Is a Recirculating Extractor Fan the Right Choice? A recirculating extractor fan may be appropriate in a number of commercial scenarios, particularly when combined with bespoke design and high-quality filtration. Urban and City-Centre Buildings  In built-up cities like Glasgow, buildings often present challenges for traditional extraction. Limited roof access, neighbouring properties, or planning constraints can make external ducting difficult or costly. Recirculating systems can offer a practical alternative when properly engineered. Retrofit Projects  Older buildings were not always designed with modern ventilation requirements in mind. Installing new duct routes can be disruptive and expensive. A recirculating extractor fan may reduce the need for invasive building works. Listed or Architecturally Sensitive Properties  Where maintaining the external appearance of a building is essential, recirculating systems can help avoid visible vents or louvres. Specific Commercial Applications  Certain businesses, such as light food preparation areas, cafés, staff kitchens or specialist workspaces, may be suitable for recirculating extraction when supported by appropriate filtration and airflow design. The Importance of Bespoke Design One of the most common mistakes with recirculating extractor fans is assuming they are ‘off the shelf’ solutions. In reality, their performance depends heavily on the correct specifications. Sigma Engineering takes a design-led approach to commercial ventilation, meaning each system is engineered around the client’s building, usage and environmental goals. Based in Irvine, Ayrshire, Sigma Engineering works across Glasgow and Central Scotland designing, manufacturing and installing bespoke ventilation and extract systems. Rather than forcing a standard product into a space, they assess airflow requirements, filtration needs, noise levels, maintenance access and long-term energy efficiency. This is particularly important for recirculating systems, where filtration performance directly affects air quality. Compliance and Air Quality It is important to note that not all environments are suitable for recirculating extraction. Commercial kitchens, healthcare settings and industrial spaces may be subject to specific regulations that dictate when air must be discharged externally. One of our experienced ventilation engineers  can assess whether a recirculating extractor fan can meet local requirements or whether a ducted or hybrid solution is necessary. Sigma Engineering regularly works with NHS authorities, hospitality venues and corporate clients, ensuring systems are compliant as well as effective. Making the Right Decision Choosing between a recirculating extractor fan and a ducted system is not a simple yes-or-no decision. It requires a clear understanding of the building, its use, and long-term expectations. Working with a specialist like Sigma Engineering  ensures that the system is not just installed, but properly designed, engineered and supported.  With experience across a wide range of sectors and a focus on bespoke, environmentally conscious ventilation systems, we help businesses across Glasgow and Central Scotland find solutions that genuinely fit their needs.

Maintaining clean, safe air in the workplace is not optional. For many industries, it is a legal requirement and a core part of protecting staff, visitors and the wider environment.  Local Exhaust Ventilation (LEV) systems play a vital role in removing harmful airborne contaminants at source, but they only work effectively when they are properly designed, installed and regularly tested. Sigma Engineering provides professional LEV testing and local exhaust ventilation inspections  for commercial and industrial clients across Glasgow and Central Scotland. Based in Irvine, Ayrshire, the company designs, manufactures, installs and maintains highly efficient, environmentally responsible ventilation systems built to last. What Is Local Exhaust Ventilation? Local Exhaust Ventilation is a mechanical system designed to capture dust, fumes, vapours, grease or mist at the point they are produced. Instead of allowing contaminants to spread through a building, LEV systems extract them directly, protecting indoor air quality and reducing exposure risks. LEV is commonly used in commercial kitchens, manufacturing facilities, workshops, laboratories and industrial settings. Systems often include hoods, ductwork, fan systems and discharge points such as anti-vandal weather louvres, all working together to remove contaminated air safely. Why LEV Testing and Inspection Matters Over time, ventilation systems can lose efficiency. Fans wear, ductwork becomes blocked and airflow levels change. Without regular inspection and testing, a system may no longer provide adequate protection, even if it appears to be running. In the UK, the Control of Substances Hazardous to Health (COSHH) regulations require most LEV systems to be thoroughly examined and tested at least once every 14 months. These inspections confirm that the system is performing as intended and continues to protect workers from harmful airborne substances. Failure to carry out LEV testing can result in non-compliance, enforcement action and increased health risks. More importantly, it can compromise the wellbeing of people using the space every day. Sigma Engineering’s Approach to LEV Testing Sigma Engineering  takes a practical, engineering-led approach to LEV inspections. Our ventilation engineers understand how systems work in real environments, not just on paper. Each LEV test includes a thorough examination of airflow performance, fan systems, duct integrity and capture effectiveness. Where issues are identified, clear recommendations are provided, focusing on achievable improvements rather than unnecessary replacements. Because Sigma Engineering designs and manufactures bespoke ventilation systems, they are well placed to assess both standard and custom-built installations. This experience ensures inspections are accurate, relevant and grounded in real-world performance. Supporting Indoor Air Quality Across Glasgow and Central Scotland Poor indoor air quality affects productivity and our comfort and long-term health. In commercial buildings, especially those with high heat loads or airborne contaminants, ventilation systems must work efficiently to maintain safe conditions. Sigma Engineering supports businesses across Glasgow and Central Scotland with solutions that go beyond basic compliance. From kitchen extract systems in busy hospitality environments to industrial LEV systems and fan installations, our work is tailored to the demands of each site. By focusing on high-efficiency ventilation and effective local exhaust capture, Sigma Engineering helps clients create cleaner, safer workplaces while reducing unnecessary energy use. Environmentally Responsible Ventilation Systems As stewards of the environment, Sigma Engineering places sustainability at the centre of every project. Efficient ventilation is not just about the movement of air. It is about moving the right amount of air, in the right way, using best-in-class technology. Well-designed LEV and extract systems  reduce energy waste, minimise heat loss and extend equipment lifespan. This approach supports corporate environmental goals while lowering running costs over time. From eco-friendly fan systems to durable, anti-vandal weather louvres designed for long-term outdoor performance, Sigma Engineering delivers solutions that balance performance with environmental responsibility. Bespoke Systems for Corporate Clients No two workplaces are the same. Off-the-shelf solutions rarely provide the best results, particularly in complex commercial or industrial environments. Sigma Engineering works closely with corporate clients to design bespoke ventilation and local exhaust systems that meet operational needs, regulatory requirements and sustainability targets. Whether installing new systems or inspecting existing infrastructure, the focus is always on long-term performance and reliability. Their in-house capabilities allow for tailored designs, precision manufacturing and professional installation, ensuring each system integrates seamlessly with the building and its use. Why Choose Sigma Engineering for LEV Inspections? Choosing the right partner for LEV testing is about more than ticking a compliance box. It requires technical expertise, clear communication and a commitment to quality. Sigma Engineering combines hands-on engineering experience with a strong environmental ethos. Based in Irvine, Ayrshire, their team works across Glasgow and Central Scotland, delivering dependable ventilation solutions for businesses that value safety, efficiency and sustainability. From local exhaust ventilation inspections to complete ventilation system design and installation, Sigma Engineering provides a trusted, end-to-end service that keeps workplaces compliant and air quality under control. For more information, don’t hesitate to contact our team today.

Running a commercial kitchen is never simple. Heat, grease, fumes and constant pressure mean your extraction and ventilation system must work hard every day. When it doesn’t, safety suffers, energy costs rise and issues with compliance appear fast.  Sigma Engineering  helps kitchens stay efficient and fully compliant through expert design, installation and maintenance of commercial extraction and canopy systems.  This guide breaks down what you need to know to stay on top of performance, safety and the law. Why Extraction in a Commercial Kitchen Matters A commercial kitchen produces smoke, steam and grease at a scale far beyond domestic cooking. Without a reliable kitchen extract system, these pollutants build up and create risks that range from fire hazards to poor air quality.  A well designed commercial kitchen extractor fan and canopy system captures pollutants at source, pulls them through a controlled duct path and releases or filters them safely. For any business with cooking equipment, proper ventilation is not just an option. It’s vital for fire safety compliance, helps meet insurance requirements and keeps staff comfortable. It also protects equipment from grease building up which reduces breakdowns and keeps running costs under control. The Role of Canopy Systems The kitchen canopy is the first point of capture. A good canopy should sit directly above appliances, draw fumes efficiently and maintain a steady airflow.  Canopies for commercial kitchens  come in different forms, including wall mounted, island and condensate canopies. When specified correctly they remove smoke and grease before they escape into the kitchen space. A commercial extraction canopy works best when matched with the correct canopy extractor fan. The right pairing ensures enough airflow to meet demand without creating noise, vibration or unnecessary energy consumption. Sigma Engineering ensures each canopy and fan combination meets the kitchen’s operational load and layout. Extraction Fans and Filtration Once pollutants are captured by the canopy they move through a ducted system driven by a commercial canopy fan. This fan must maintain consistent airflow regardless of the cooking load.  Your options range from traditional fans to more advanced systems such as recirculating extractor fans fitted with filtration units. Filtration helps remove particulates and grease before air is discharged or recirculated. Solutions vary from simple mesh filters to high performance filtration ventilation units used in more demanding environments. Where cleaner air is essential, HVAC filtration and industrial air filtration and ventilation systems can support overall indoor air quality. Ensuring Compliance: LEV Testing and Inspection One of the most important compliance tasks for any commercial kitchen is keeping up with Local Exhaust Ventilation testing. LEV testing ensures your extraction system is removing contaminants effectively and meets HSE standards. Failure to comply can lead to enforcement action and puts staff at risk. Local Exhaust Ventilation inspection covers airflow checks, capture efficiency, filter condition and the general integrity of the system. Sigma Engineering provides full LEV system inspection and LEV extraction testing to verify performance. Regular local exhaust ventilation LEV testing proves your system is fit for purpose and supports safe working conditions. Kitchen Extract Systems and Fire Safety Grease is one of the biggest fire risks in a kitchen. A poorly maintained kitchen smoke extractor or duct system can allow grease to accumulate in places that are hard to reach. This is why routine cleaning and testing are essential. Kitchen extract systems must be designed to minimise build up and allow thorough cleaning. Sigma Engineering installs systems that meet fire safety guidelines and provides ongoing maintenance to keep them compliant. A clean duct system protects both staff and customers and reduces emergency downtime. Heat Recovery and Energy Efficiency Many commercial kitchens now look for ways to cut the energy usage without affecting the performance. Heat recovery ventilation systems can make a big difference. A heat recovery unit, sometimes known as an HRV system or MVHR system, captures heat from outgoing stale air and uses it to warm incoming fresh air. This reduces heating demand and supports a more balanced indoor climate. Commercial heat recovery solutions include ERV systems, heat recovery ventilators and full commercial MVHR units. These systems improve efficiency, reduce energy bills and support sustainability goals. Sigma Engineering designs and installs commercial heat recovery ventilation systems that integrate with existing kitchen ventilation for maximum benefit. Choosing the Right Partner Commercial kitchen extraction is a specialist field. A system that looks fine on paper can fail in practice if the design is incorrect or the airflow is mismatched. Working with an experienced engineering partner ensures smoother installation, easier maintenance and long term safety. Sigma Engineering brings expertise across extraction, filtration and heat recovery. From commercial exhaust canopy design to full kitchen ventilation fan replacements, the company provides tailored solutions based on the specific needs of each site. We’re proud to support businesses with dependable engineering, expert compliance checks and efficient ventilation systems built to last.  If your kitchen extraction system needs upgrading, simply contact our team for more information.

At Sigma Engineering , we understand that effective ventilation is not just about the movement of air: it’s about health, sustainability and operational efficiency.  Based in Irvine, Ayrshire, and serving clients across Glasgow and Central Scotland, we specialise in designing bespoke, high-performance ventilation and extract systems for commercial buildings. Let’s look at the key considerations for choosing the right heat recovery ventilation system for your building, whether it’s an HRV (Heat Recovery Ventilation) or MVHR (Mechanical Ventilation with Heat Recovery) solution. Why Heat Recovery Ventilation Matters in Commercial Buildings In a commercial setting, ventilation  is crucial for maintaining air quality, controlling humidity and complying with building regulations. But standard systems often result in significant heat loss, leading to higher energy costs and environmental impact. Heat Recovery Ventilation solves this by capturing warmth from outgoing stale air and using it to preheat the fresh air being drawn in. This reduces the energy needed to condition air indoors, lowers carbon emissions, and enhances people’s comfort year-round. At Sigma Engineering, we take this a step further with award-winning heat recovery technologies, tailored to meet the complex demands of modern commercial buildings. HRV vs MVHR: What’s the Difference? While HRV and MVHR are often used interchangeably, there are subtle differences: HRV systems primarily recover heat from outgoing air to warm incoming air. MVHR systems offer full mechanical ventilation with both extract and supply fans, managing airflows across multiple zones. MVHR is typically more advanced, offering better control and more efficient air distribution – particularly beneficial in larger or multi-use commercial spaces. Both systems reduce reliance on traditional heating systems and improve environmental performance, but choosing the right configuration depends on the layout, use, and energy goals of your building. Factors to Consider When Choosing a Heat Recovery System 1. Size of the Building and Use A ventilation system for a busy commercial kitchen or manufacturing facility must meet entirely different requirements from that of a school, office or retail space. Our engineers assess airflow needs, occupancy patterns and zoning complexity to recommend the most efficient solution. 2. Energy Performance Targets If you're working towards BREEAM certification or targeting low operational carbon, you need more than an off-the-shelf solution. We specialise in bespoke ventilation systems that support energy-saving goals and exceed building regulations in Scotland. Our advanced Electronically Commutated (EC) fan technology offers precise control and exceptional efficiency, reducing whole-life costs while delivering long-term performance. 3. Installation Constraints and Integration Every commercial building is unique. That’s why Sigma Engineering offers full in-house design and manufacture, ensuring seamless integration with your building’s architecture and mechanical systems. Our team works closely with architects, consultants and contractors from the planning stage onwards, providing the documentation and technical data required for building warrants and regulatory compliance. 4. Air Quality Requirements Air quality has moved to the top of the agenda for commercial buildings, especially in the wake of COVID-19. Our systems are designed not just to move air, but to improve it, reducing CO₂ levels, removing airborne pollutants and maintaining a healthy indoor environment for occupants. Why Choose Sigma Engineering? We are one of Scotland’s leading experts in energy-efficient ventilation. What sets us apart is our commitment to innovation, sustainability and customer communication at every step. Advanced Fan Wall Configurations: Our modular fan wall systems deliver unmatched reliability and redundancy, ensuring consistent airflow even in critical applications. Proven HRV Technology: Designed and tested in-house, our heat recovery systems offer industry-leading thermal efficiency and proven results in actual commercial environments. Fully Integrated Design: We take full ownership of the system, from design and manufacture through to installation support and maintenance planning. Local Knowledge, National Standards:  Based in Ayrshire, our team knows the Scottish climate, regulations and construction industry inside out. We bring the best of both worlds: local service with national-level expertise. Reducing Costs and Carbon Our systems have been implemented across a wide range of commercial projects, from schools and office buildings to hotels and industrial facilities. In each case, our clients report: Lower heating and cooling bills Improved EPC and BREEAM ratings Enhanced indoor air quality Fewer maintenance issues due to first-class engineering and quality control We don't just supply ventilation: we engineer solutions that perform for the long haul. Working With Sigma Engineering Whether you’re designing a new building, refurbishing an older space or upgrading to meet new environmental targets, Sigma Engineering can deliver a ventilation system that works, now and into the future. Our engineers pride themselves on their hands-on, collaborative approach. We’re here to listen, guide and deliver, working directly with your architects, M&E consultants or contractors to keep everything on track. Get in Touch If you’re planning a commercial project in Glasgow, Central Scotland or beyond, and need an efficient, environmentally responsible ventilation system, simply contact our team at Sigma Engineering. We’ll help you choose the right HRV or MVHR solution to match your building’s demands, reducing energy use, enhancing comfort and improving long-term value.

Industrial environments, whether they’re commercial kitchens or manufacturing plants, are prone to airborne hazards. Dust, fumes, smoke, vapours and chemical particles don’t just compromise people’s comfort: they risk your staff’s health and safety. They can also have an impact on legal compliance.  At Sigma Engineering , we’ve made it our mission to solve this problem with the finest quality air filtration and ventilation systems that protect both people and the planet. Headquartered in Irvine, Ayrshire and operating across Glasgow, Edinburgh and Central Scotland, we’re trusted ventilation engineers delivering bespoke solutions for commercial and industrial spaces. Whether it’s a high-efficiency kitchen extractor or a custom-built local exhaust ventilation (LEV) system, we help businesses breathe easier, literally. The Hidden Dangers of Poor Air Quality Indoors Workplace air quality isn’t just a matter of comfort. It’s vital for people’s health, along with compliance and operational efficiency. Without proper air filtration and extraction, workplaces can accumulate: Toxic fumes from welding, soldering and solvents Grease-laden vapours in kitchens Dust and particulates from cutting, grinding or sanding Mould spores and allergens in poorly ventilated spaces Exposure to such contaminants can cause a range of health issues, from asthma and irritated skin to long-term respiratory disease and cancer. According to the Health and Safety Executive (HSE), thousands of workers in the UK suffer each year from illnesses linked to poor air quality, many of which are preventable. Industrial and commercial kitchens, in particular, face unique challenges with ventilation. Without a reliable kitchen extraction system, grease vapour builds up fast, posing not just a hygiene risk, but also a serious fire hazard. Why a Local Exhaust Ventilation (LEV) Makes Such a Difference Unlike general ventilation, LEV systems are designed to capture harmful airborne substances at the source; in other words, before they spread into the wider workspace. At Sigma Engineering, we design, manufacture, and install LEV systems that are tailored to the specific processes and risks of each site. Our wide range of solutions include: Custom-built extract hoods and canopies State-of-the-art impeller designs Electronically Commutated (EC) fan technology for energy-efficient performance Patented heat recovery systems that cut emissions and running costs Every component is engineered with whole-life cost and environmental impact in mind. Safer Kitchens  with More Efficient Extraction For commercial kitchens, extractor systems have become an essential feature. High temperatures and constant cooking lead to intense volumes of heat and grease vapour. Without proper ventilation, staff are left working in uncomfortable and dangerous conditions. Sigma’s bespoke kitchen extraction systems combine stunning designs with reliable performance. We deliver systems that: Remove grease vapours and smoke quickly and effectively Reduce fire risk by managing airborne grease build-up Improve thermal comfort for kitchen staff Support hygiene compliance and indoor air standards And thanks to our EC fan technology and advanced airflow control, our systems run efficiently, cutting noise, energy levels and maintenance costs. Compliance with HSE & COSHH Regulations Under the UK’s Control of Substances Hazardous to Health (COSHH) Regulations, employers are legally required to control exposure to hazardous substances in the workplace. Ventilation and extraction systems play a central role in achieving COSHH compliance. But it’s not just about installing the right system: it’s also about maintenance, testing, and verification. At Sigma, we offer full lifecycle support for our systems, including: System commissioning and airflow testing LEV inspection and maintenance services Advice on COSHH assessments and ongoing compliance This ensures your site doesn’t just meet regulations, it stays ahead of them. Going Green: Efficiency That Pays Off At Sigma Engineering, sustainability isn’t a buzzword: it’s built into every system we design. Our advanced ventilation solutions are engineered to: Reduce energy use through heat recovery and smart fan control Lower carbon emissions across the system’s lifespan Improve indoor air quality without sacrificing performance Whether it’s a kitchen canopy in Glasgow or a full LEV system for a manufacturer in Edinburgh, our systems are designed with energy efficiency and environmental impact in mind. Cleaner air, lower bills, and a smaller carbon footprint, that’s the Sigma difference. Why Choose Sigma? From the first site survey to the final installation, Sigma Engineering delivers ventilation systems that truly deliver. We’re not just engineers: we’re problem-solvers. Our team of specialists brings decades of experience in: Ventilation system design and airflow modelling Fabrication and installation across a wide range of industries Ongoing service and support for long-term system performance Our team always tailors solutions to your space and business. We appreciate that every space has its own challenges, which is why we build systems that meet them head-on: efficiently, safely, and sustainably. Get in Touch If you operate a commercial kitchen, workshop, or any industrial site where air quality matters (and it always does), talk to the ventilation experts. Sigma Engineering Product Design Ltd provides tailored ventilation and extraction systems across Glasgow, Edinburgh, and throughout Scotland. Breathe easier. Work safer. Choose Sigma.

This is the air we breathe! "Just open the window". It's a common 'solution' in kitchens, bedrooms, offices and classrooms. But to tell you the truth, it doesn't do the job. Cracking the window in an office where the air feels suspiciously stuffy by 10 am doesn't fix your problem and is definitely not practical. Cracking open a window is not a ventilation strategy; it's a quick fix (and a guaranteed complaint from whoever's parked nearest to the window). Opening the windows during winter makes your staff freeze (just ask the guy who brings a blanket to every meeting), while opening them in summer lets in pollen from the outdoors and aggravates your poor office lady's hay fever. Not to mention, you could be inviting all of the outdoor pollution into your space to be breathed in. How kind! The reality in today's world is that the air outdoors is polluted and it's definitely not what it used to be. Fresh outdoor air is often thought of as the gold standard—natural, refreshing, pure. But here’s a comparison that flips that perception on its head: Rainwater is also natural .  Yet, none of us would dare drink it straight from the sky. Why? Because we understand it carries pollutants—dust, microbes, industrial residues—from the atmosphere. It’s why we filter and purify water before it ever reaches our glass. So, here’s the question:If we won’t drink unfiltered water, why are we so willing to breathe unfiltered air? Outdoor air today is saturated with more than just oxygen and nitrogen. It's filled with CO₂, particulate matter, volatile organic compounds (VOCs), allergens, and microbial contaminants. In urban areas, it also contains emissions from vehicles, industrial activity, and even microplastics. Yet, despite breathing 11,000 litres of air per day, most of us take in every breath without a second thought—no filter, no barrier, no protection. Opening the windows allows air exchange, but its uncontrolled and one-directional. You're letting your dirty air flow out of the window, and outdoor dirty air flow in. Swapsies! Studies show that indoor air can be 5x more polluted than outdoor air, this is due to the lack of airflow, which allows CO2 to build up, and dust, dirt and VOCs to hang in the air, just waiting to be breathed in. And no, an open window at the end of the corridor can't fix that. So, what can? Sigma can. Our ventilation systems — like our Sigma360 units  — don’t rely on wind direction, temperature, or someone remembering to “air the place out.” They deliver: Constant, measured airflow Heat recovery  to keep energy bills low Smart CO₂ monitoring Multi-stage filtration  for allergens, dust, and airborne pathogens All of it working silently, efficiently, and automatically — whether it’s July or January. At Sigma EPD, we see this as a fundamental gap in how we approach health and sustainability. Clean air, like clean water, should be a basic standard—not a luxury. And just as water treatment revolutionized public health in the last century, air purification is the next frontier. It’s time to stop treating clean air as optional. Because just like contaminated water, polluted air harms our health silently, daily, and cumulatively. The natural world gives us both air and water—but nature doesn’t pre-clean them for modern pollution. That’s our responsibility.

It is the simplest things in life that can have the biggest impact on the world’s greatest and most-baffling problems. But once discovered, their effectiveness and basic principles never change. In the case of the novel coronavirus, simple things like the washing of hands, the wearing of masks, and the application of the basic principles of ventilation,  can capture and remove harmful substances from our breathing zone and can have an effective and lasting impact against COVID-19 and other viruses.   We all hope that a vaccine will be found in the short term. However, current projections for a vaccine is the end of 2020, but in reality it may not become available for wide distribution and uptake until early to mid 2021. Further, there are questions around the rate of uptake, whether or not boosters would be required and how long immunity would last when vaccinated. The short and long response to these questions is that we do not have these answers. In reality we may not be able to eradicate this virus for some time. Some scientist estimate two years or longer.  In the mean time we need to take a two-pronged approach: • Yes, we work in anticipation of a vaccine, wash our hands, keep our distance, and wear our masks. • But, we must also improve ventilation. We need to add "V" for ventilation to the governments acronym FACTS. Because, VFACT is  that well designed ventilation would reduce the viral load in enclosed spaces, making it possible to reopen more safely and sustainably. Simple things first

At last, the importance of ventilation as a tool against  COVID- 19 is being recognised.  The Guardian Saturday 24 October 2020 Nicola Davis Science correspondent UK could be urged to keep windows open in effort to curb Covid-19 Scientists call for information campaign as evidence on role of poor ventilation mounts Britons could be urged to throw open the windows in an effort to keep coronavirus at bay as scientists call for a public information campaign to stress the importance of ventilation in reducing its spread. A paper by the Environmental and Modelling group for the government’s Scientific Advisory Group for Emergencies (Sage), dated 30 September, reveals concerns over the role of poor ventilation in the spread of the coronavirus, noting evidence that suggests insufficient airflow could increase the risk of transmission from tiny airborne particles known as aerosols that can carry the virus more than 2 metres. “Ventilation should be integral to the Covid-19 risk mitigation strategy for all multi-occupant public buildings and workplaces,” the team write. Prof Linda Bauld, an expert in public health at the University of Edinburgh, welcomed the emphasis on fresh air. “It is a really, really important topic that has not been given enough attention,” she said, noting that a number of outbreaks, including those involving choirs, have raised concerns over airborne transmission. The report urges the creation of a public information campaign on the issue. “A simple public guide on ventilation should be developed with reasons why ventilation is important, practical tips and/or FAQs,” the report notes, citing similar campaigns on the importance of handwashing and face coverings. Bauld noted that neither the UK messaging around “hands, face, space” nor the Scottish Facts campaign mention ventilation. But she added that information on ventilation would depend on the setting, meaning more complex messaging – a problem the report acknowledges. “Assessing ventilation in many environments requires engineering expertise, and mitigation measures are setting specific taking into account the nature of the building and users, ventilation type, length of exposure and activity,” the report notes.. Bauld added that in many settings, ventilation would involve a simple approach. “How are you going to get airflow in an enclosed indoor space? In most situation in the UK it is absolutely just about windows and doors,” she said. Dr Shaun Fitzgerald, from the University of Cambridge who contributed to the new report, said ventilation had been mentioned in government news meetings. But, he stressed, more needed to be done to highlight its importance, noting in his experience this was particularly necessary for smaller businesses such as convenience stores, independent coffee shops and hairdressers. “We need to raise the awareness, especially in colder weather where the natural inclination has been, for many places, which are possibly not well-designed, to close the windows and close the vents,” he said. According to the report: “Under steady state well-mixed conditions for the same duration, models suggest that exposure to aerosols approximately halves when the ventilation rate is doubled.” But while the report stresses the importance of ventilation, it says other factors must also be considered such as “thermal comfort”, exposure to pollution and energy use.

A Colleague of mine sent me this BBC news article. I wanted to share because at Sigma EPD we also believe that well designed ventilation is central to defending our family, friends, customers and employees from this and other pandemics and viruses year on year. Our defence is a Robust Ventilation Strategy (RVS) going forward. Please read below. Covid-19: Five ways to avoid catching the virus indoors By David Shukman BBC News science editor   Good ventilation could be the key to avoiding coronavirus as autumn approaches and people spend more time indoors. For months we've been told to wash our hands and maintain social distancing to beat coronavirus. But scientists and engineers say we also need to think about the air we breathe, as children go back to school and more people return to offices. Good ventilation matters in five ways. 1: If it's stuffy, walk away When you walk into a room and the air feels stale, something is wrong with the ventilation. Not enough fresh air is being introduced, which increases your chances of getting infected by coronavirus. Recent research shows that in confined spaces there can be "airborne transmission" of the virus - with tiny virus particles lingering in the air.  According to workplace regulations set up before the pandemic, everyone should get 10 litres of fresh air every second, and that matters more than ever now. So if a place seems stuffy, just turn around and leave, says Dr Hywel Davies, technical director of the Chartered Institution of Building Services Engineers. He says that it's vital to have a flow of clean air: "If you've got someone who's infected in a building, and you're bringing in plenty of outside air, you're diluting whatever infectious material they're giving off. You're reducing the risk of other people becoming infected." 2: Look up at the air conditioning From offices to shops, air conditioning is welcome on hot days - but check the type of unit. The simplest is a slender white box mounted on walls or ceilings, known as a split air conditioner. This draws in air from a room, chills it and then blows it back out again.  In other words, it's recirculating the air. This is no problem for a quick visit but may be a risk over a period of hours. A study of a restaurant in China blamed this type of air conditioner for spreading the virus. One customer was "pre-symptomatic" - in other words, he was infected but did not realise because he had yet to develop symptoms.  Scientists reckon he released the virus as he breathed and talked, and it was pushed around the room by swirling air currents from the units on the wall. The result was that nine other people became infected. Dr Davies points again to the importance of fresh air:  "If there had been a good supply of outside air, very likely fewer people would have become infected - if any." 3: Ask about the 'fresh air ratio' In a modern building where the windows are sealed, how can you get enough fresh air? You're relying on a ventilation system in which stale air is extracted from the rooms and piped to an air handling unit, often on the roof. image caption A rooftop air conditioning unit There, fresh air can be pulled in from outside and mixed with the old inside air, before being sent back into the building. Given the risk of coronavirus infection, the professional advice is to maximise the fresh supply. "Having 100% outside air or close to 100% is a good thing," says Prof Cath Noakes of the University of Leeds and chair of the environmental panel of the government's SAGE advisers, speaking in a personal capacity. "The more fresh air, the less you're running the risk of recirculating the virus through the building." The precise mix is decided by the building's managers, who may be working for the owners or the tenants. . The drawback to running 100% fresh air is the cost - the incoming air has to be heated in winter and cooled in summer, all of which requires energy. 4: Check if there's virus in the filters A modern ventilation system will have filters but these are not fool-proof. In the US, researchers investigating the Oregon Health & Science University Hospital found that traces of coronavirus were trapped by the filters but some had somehow slipped through. Prof Kevin van den Wymelenberg, who led the project, believes that swabbing the filters could reveal if there's someone infected working in a building. In South Korea, a call centre on the 11th floor of an office building saw one person infect more than 90 others.  If the filters had been checked more frequently, the presence of the virus might have been spotted sooner. Prof van den Wymelenberg says data from filters can "show us where to punch and when to punch" in tackling infections. 5: Watch out for draughts Talk to any expert in the field and they will say that fresh air is the key. But one specialist in modelling the movement of air says it's not that simple. Nick Wirth used to design Formula 1 racing cars, and now advises supermarkets and food-processing companies on how to manage air flow to keep people safe.   He worries that if someone sitting beside an open window turns out to be infectious, they could shed virus to others downwind. "If you open a window, where is the air going to go?" he asks. "We don't want people in a direct line of that airflow. "More fresh air in general is better but if it's flowing horizontally and full of virus it could have unintended consequences." I put this scenario to Prof Cath Noakes. She says the benefits of plentiful fresh air diluting the virus will outweigh any risks. An open window might lead to more people receiving the virus but in smaller, less risky amounts, in her view. It's no surprise there are disagreements - there's a lot we still don't know about the virus. But the air we breathe is bound to be part of any effort to make buildings safer. See other Sigma post on our website blog ( Sigmaepd.com )

How can you reassure them So, it’s official. Scotland is reopening! However, after conversations with friends, colleagues and family, there seems to be a distinct lack of confidence as it relates to re-entering enclosed public places including restaurants, where the wearing of a mask would encumber our ability to engage in social activities such as eating and drinking.  The reality is, in this country, we spend most of our winter months indoors. It is also a fact that every year the National Health Service (NHS) is brought to breaking point by one virus or the other. Every year many people become ill, some more so than others. As a society, we spend millions on extra manpower, software and hardware to bolster the NHS for the next yearly wave.  ‘We’ll be ready next year!’ So we tell ourselves only to discover that the goal post has moved once more - the NHS is on its knees again despite the heroic efforts of all NHS staff. But what if we are looking at this from the wrong perspective? What if we are trying to push the brolly up from the wrong end? Could it be that infection rates are higher than necessary, giving rise to hospitalisation and death? The link between infection rates and the combination of poor air quality and patterns of air movement in enclosed public places is a point for critical focus. We can improve the health of our nation by addressing issues related to quality of air and the pattern of air movement that is served to us in public places.  A few years ago, smoking was banned in public places because of the impact of second-hand tobacco smoke on people sharing the same enclosed space. Some would remember the smell of tobacco wafting over from a smoker some distance away. Why is this important? Well, our experience of tobacco smoke gives us a tangible illustration of how very small particles can be carried in air. When subject to the same aerodynamic forces, aerosols behave in the same way as the tobacco smoke.  The thing is this. For months prominent scientists from around the world have advocated for recognition that COVID-19 can be carried by aerosols (fine spray). The World Health Organisation (WHO) recently conceded that this could be the case. Now, if COVID-19 can remain suspended in air, and lingers in the atmosphere, then it is highly likely that the other coronaviruses that threaten to decimate the NHS every year also behave in the same manner - lingering in the air that we breathe indoors. If the above is true, and we have no reason to doubt that it is, then a better and more ‘Robust Ventilation Strategy’ needs to be put in place as part of our public health policy. We need to capture and remove this and other viruses from enclosed public spaces as an immediate response to the present threat and to future proof our society against other viruses that would threaten to undo us.  We must decide whether we want a permanent fix or are willing to endure the endless yearly cycle of sick days, ill-health and death.  Are we going to be ready with a robust response if or when the next virus or disease strikes?  As other countries reopen public places ahead of us, we can see a pattern of opening and closing emerging, as public places of different types become hot spots for the virus. It is widely accepted that going into public spaces with poor ventilation gives rise to infections. Unarguably, quality ventilation must be central to reopening safely and permanently.   There are three basic constituents of a good quality ventilation strategy:  1. Correct levels of extract 2. Correct levels of supply or make up air 3. A definitive air pattern - how the forces induced by supply and extract cause the air to move in a way that minimises human contact with the virus.  Given the trepidation that exists around the reopening of indoor public spaces, there are a couple of salient questions that need to be addressed. What can business owners do to protect and bolster the confidence of customers and staff? And, how can you reassure them that you have done everything you can to protect them? Well, in addition to social distancing and sanitation measures, Sigma Engineering Product Design (SigmaEPD) suggests the following: • Implement measures such as effective ventilation that would reliably remove viruses contained in aerosol. A well-designed ventilation system is also effective in removing larger virus-carrying droplets that may settle on surfaces. Additionally, you can ensure that the air movement induced by your ventilation system leaves no regions of stagnant air, thus minimising hiding places for the virus.   • Ultraviolet Germicidal Irradiation (UVGI) and some other filtration systems can be used to kill viruses in confined spaces. These can Ideally be used in conjunction with mechanical or natural ventilation. • Publicise the steps that you have taken to remove or kill virus particles that would otherwise linger. Please contact Sigma Engineering Product Design Ltd (SigmaEPD) for further information on:  P  : 01294203374 M : 07821256603 E  : Info@sigmaepd.com W: www.sigmaepd.com

Extracting The Virus As social distancing is being relaxed in England and would soon become a reality here in Scotland, let us use this time wisely. It is important that every establishment has a clear ventilation strategy that would help control the spread of the coronavirus. Please see tips from the Federation of European heating, Ventilation and Airconditioning Associations (REHVA) guidance document below. “Latest studyxvii concluded that aerosol transmission is plausible, as the virus can remain viable in aerosols for multiple hours. Another recent studyxviii that analysed superspreading events showed that closed environments with minimal ventilation strongly contributed to a characteristically high number of secondary infections.”  Summary of practical measures for building services operation.  1. Secure ventilation of spaces with outdoor air  2. Switch ventilation to nominal speed at least 2 hours before the building usage time and switch to lower speed 2 hours after the building usage time  3. At nights and weekends, do not switch ventilation off, but keep systems running at lower speed  4. Ensure regular airing with windows (even in mechanically ventilated buildings)  5. Keep toilet ventilation 24/7 in operation  6. Avoid open windows in toilets to assure the right direction of ventilation  7. Instruct building occupants to flush toilets with closed lid  8. Switch air handling units with recirculation to 100% outdoor air  9. Inspect heat recovery equipment to be sure that leakages are under control  10. Switch fan coils either off or operate so that fans are continuously on  11. Do not change heating, cooling and possible humidification setpoints  12. Do not plan duct cleaning for this period  13. Replace central outdoor air and extract air filters as usually, according to maintenance schedule  14. Regular filter replacement and maintenance works shall be performed with common protective measures including respiratory protection.  SigmaEPD - Great air quality in any environment.