How to Avoid a Roof Penetration

Reduce Thermal Heat Loss with the Studor Maxi-Vent


The Maxi-Vent fits neatly into the roof space

With modern improved building insulation methods and the importance of reducing thermal heat loss, not compromising the roof’s integrity with penetrations (such as vent pipes) is of great benefit – this is where the Maxi-Vent, together with the associated reduced material and labour savings, provides an environmentally friendly option for the building versus traditional drainage ventilation systems.

Saving Time and Money

The Maxi-Vent is very easy to fit and it will decrease the amount of work and piping – you no longer need to penetrate the roof of a property. It is favoured in residential homes, flats and commercial buildings of any height, and its benefits lead to both cost and time savings.

Protecting Your Living Environment

This advanced AAV protects the trap seals in the drainage system by allowing the intake of air, so a soil pipe can maintain the right level of pressure within the drainage system. By instead installing the Studor Maxi-Vent, the vent pipes terminate in the roof space or lower down the waste system, therefore completely eliminating excessive thermal heat loss and a roof penetration. In addition, it also means that any bad smells will be kept well away from a building’s Air Handling Units (AHUs).

Below is a short video which introduces the Studor Maxi-Vent. More information is available on the Studor Maxi-Vent product page.


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Studor Test Tower in the Press

We’re delighted that the Studor Test Tower has received coverage in the industry press, recognising the importance of this installation in that it offers industry professionals the opportunity to see the evidence that the Studor System works in real life.

You can read the latest articles in the following publications – HPMMagModern Building Services and Society of Public Health Engineers.

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Learning about Building Design in the Big Apple

A Guest Blog from Steve White

Between 26 and 30 October, 2015, I was invited to attend the Council on Tall Buildings and Urban Habitat conference at the Grand Hyatt, New York. This was the first time I’d attended the event, and as a manufacturer in specialist drainage ventilation, I hoped the event would provide an insight into the activities around the world for high-rise buildings, both now and in the future.


The event was attended not only by building services engineers, but also by developers, architects and leading consultants from 45 countries, representing 140 cities across the globe.

A total of 125 papers were presented in total, but my particular interest was in the papers on the Kingdom Tower in Jeddah and the Developments in East Asia. Hearing the views of the architects was interesting in learning how their designs are originated – it is definitely not just to do with making the buildings unique and pretty!


I came away from the conference with a much greater understanding of what goes into the design of tall buildings and towers. It also reinforced to me that these buildings need the Studor System to make them work. No matter how tall, expensive and iconic these buildings are, if they smell they smell, and we, at Studor, have the solutions to prevent bad drainage odours from spoiling the experience of the inhabitants.

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Drusillas Animal Park Returns to Studor for Sewer Gas Solution

Drusillas LogoBackground

Having already solved major sewer gas problems by installing several Maxi-Filtra vents in the past, Drusillas Park, a popular small animal zoo in East Sussex, contacted Studor to obtain Studor vents to prevent problems occurring in an area of new development within the park.


A new project was in development to introduce camels, for the first time, into Drusillas’ roxy-and-lofty-the-camels-at-drusillas-park-1-206llama paddock. However, underneath the paddock was a 45,500 litre sewage balancing chamber which vented into the area where Drusillas wished to build the camel shelter.

Studor Solution

This was not the first time that Drusillas has encountered a problem with sewer drain venting, as they’d experienced similar issues when constructing their ‘Hello Kitty Secret Garden’ and ‘Explorers Café’. In both instances, installing a Maxi-Filtra vent from Studor instantly solved, what could have been a major problem. Therefore, they had no hesitation in requesting another three Maxi-Filtra vents for their new camel shelter.

The Studor Maxi-Filtra is a sturdy and practical vent designed specifically for outdoor applications to eliminate bad odours.


No specialist installation is required for the Maxi-Filtra; it is commonly installed with just a push-fit connector and the cap simply lifts off to enable easy access for filter cartridge replacement. The robust design means the Maxi-Filtra can be used vertically or horizontally and can be installed in hard-to-reach places.

In the case of Drusillas, it has been used to eliminate the bad odours from existing external drainage vent stacks. The Maxi-Filtra can also be used on a number of external applications, including the ventilation pipe of septic tanks, water tanks and silos.


Having being installed in three separate applications across Drusillas Park, the Studor Maxi-Filtra has proved completely successful in eliminating sewer gas emissions and the consequent unpleasant odours.

You can read the full case study here.


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Communicating and Educating

One of the really pleasurable aspects of my position as Technical Sales Director for Studor is the opportunity I have to travel to many different countries.  Also to share and communicate the knowledge I have developed about drainage systems.  There is nothing to compare to the feeling of sharing knowledge with those who WANT to learn…


Although local practices and cultures are very different, the technical challenges of drainage designs in buildings remain very similar and this is true all over the world.

As a sales person for over 20 years I have naturally been involved with prospecting, budgets, negotiations, orders and deliveries.  However, since I started my collaboration with Studor I have also had to become a “teacher”.  I must say that, despite the challenge, this has been a fantastic and rewarding role.

The ability to successfully transfer the knowledge of the world experts at Studor has been an outstanding experience, enriching myself with the pleasure of establishing fantastic personal relationships.  There is nothing better than to witness the emotion on peoples’ faces when a concept is understood!  You really feel a sense of accomplishment.

Finally I can also express my natural extrovert, enjoying the natural communication flow while speaking different languages and using skills I developed as a student when I was a tour guide in Tuscany.

Colombia, Chile, Portugal, Italy, Spain, Israel, The Netherlands, Iran, Sweden, Thailand, Panama, UAE, Qatar, Uruguay and Morocco are just some of the recent locations of my world education tour.

Whilst I try to visit as many countries as possible, please do not forget that many of the resources I use are included in the DRC (Distributor Resource Centre).  If I can assist or if you would like me to visit to help train your sales team and technical staff, please just contact me.

Best regards


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PRoBE – Pathogen Research in the Built Environment

PRoBE is a new research initiative to provide the knowledge to address the growing issues of pathogen spread in building systems.

PRoBE was established at Heriot-Watt University with the aim of characterising and defining the aerosolisation, transmission, and infection risk posed by building systems, particularly the building drainage system.

PRoBE Identity

PRoBE is a cross-disciplinary research group of engineers, mathematical modellers and microbiologists at Heriot-Watt University.  The acronym stands for Pathogen Research in the Built Environment (PRoBE).  The PRoBE logo and more information can be found at the research group website (

It is intended that this cross-disciplinary group will look at a range of different issues relating to infection spread in buildings. Having been established just over a year ago, the group has already had success in highlighting the complex issues in this area and brings a fresh approach to the discipline.

The Group is led by Dr. Michael Gormley and supported by Dr. Tom Aspray who is a microbiologist, and Dr. David Kelly who has worked on building drainage systems for over 10 years.

PRoBE Research

Bioaerosol Transmission

Bioaerosols can pose a significant risk to the spread of infection and disease within buildings. Research activities focus on the characterisation of bioaerosol generation and transmission, coupled closely with the development and application of advanced numerical models for the prediction of bioaerosol transport.

A significant area of research focuses on the transport of bioaerosols within the sanitary plumbing and sewerage system and their cross-transmission into the building. Laboratory tests, using Pseudomonas putida KT2440 as the pathogenic agent within a toilet flush, found that the generated bioaerosols could be spread from one floor of a building to another via the building drainage system. If a defect within the system exists such as, for example, the loss of the seal within a water trap, then the bioaerosols could enter a room on an upper floor and contaminate every surface within that room. Such a cross-transmission route depends on the following confirmed conditions:

  1. The sanitary plumbing and sewerage system is a reservoir of pathogenic organisms.
  2. Bioaerosols are generated during appliance flush.
  3. Airflows within the sanitary plumbing and sewerage system move both in the upward and downward directions and circulate between floors.
  4. Bioaerosols can be transported on the airflows that exist within the sanitary plumbing and sewerage system.
  5. A defect, such as an empty U-bend, allows air to move from the system into the building.

Viral Transmission in Tall Buildings

As a common feature of most global cities, tall buildings offer a number of advantages, whether it be to provide offices or homes when urban space is not available or to make an iconic statement on the world stage. However, these “cities in the sky” can also facilitate the rapid spread of infection from one person to another due to the high density of people in a single building.  Using advanced numerical modelling techniques, researchers at PRoBE were able to confirm the World Health Organisation conjecture that a high cluster of cases of SARS, reported at the Amoy Gardens residences in Hong Kong in 2003, was caused by the vertical transmission of the virus between apartments via both the sanitary plumbing system and the service risers. The 321 confirmed cases of SARS and 42 fatalities suffered by the residents highlight the risk of infection spread within buildings, especially the significance of a vertical transmission route which is particularly unique to tall buildings.

By modelling air flow movement and air pressure wave propagation within the sanitary plumbing system, the PRoBE research was able to demonstrate the likely circumstances within the building that resulted in the rapid spread of the virus. The index patient (the first resident to become infected with the virus) lived on the 16th floor of the 36 storey building. Infected faecal particles were discharged into the building drainage system during the diarrhoeal phase of the infection. The flushing of the WC caused the generation of airborne bioaerosols within the system’s vertical stack. A number of dry floor drains, together with some appliances with no fitted water trap seals, provided a route for the ingress of virus-laden bioaerosols from the building drainage system and into the bathroom, driven by the transient pressures prevailing within the system, natural buoyancy, and the negative pressure created by the bathroom extract fan. After passing through the extract fan, the bioaerosols were then exhausted into the external service riser which acted as a channel to spread the virus to upper and lower apartments via open windows.  This mechanism of viral spread was attributed to the infection of residents in some 11 apartments below the index patient and 27 apartments above the index patient – firmly highlighting the significant risk of vertical transmission of infection in tall buildings.

Infection Spread in Hospitals

With up to 9% of all patients in the UK contracting a Healthcare Acquired Infection and an associated annual cost to tax payers estimated at £1 billion, the control and reduction of the spread of infection in hospitals is a top priority for the NHS in the UK. Researchers at PRoBE have identified the building drainage system as a potentially significant, yet often forgotten, source of infection spread within hospital buildings.

The building drainage system is one of only a few engineered systems that interconnect all parts of a building, and it is the only one that acts a collection network for human waste. In a hospital building, this waste has a high potential for pathogenic contamination, making the building drainage system a potentially rich reservoir for pathogenic microorganisms. Failures within the system, such as empty water trap seals at appliances or wastewater backup due to blockages, can contribute to the spread of pathogens from the building drainage system into the hospital building – considerably adding to the risk of infection spread.

Research carried out by PRoBE in hospital buildings using polymerase chain reaction (PCR) tests on waste water samples confirmed that the sanitary plumbing and sewerage system is contaminated by pathogens released directly to the system by infected patients. In one example, the building drainage system tested positive  for Norovirus GII over a number of weeks during an outbreak within the hospital building.

Furthermore, measurement of the conditions within the hospital sanitary plumbing and sewerage system showed average temperatures of just over 24°C and an average humidity of almost 97%. The warm and humid conditions that exist within the system not only aides pathogen survival, it also facilitates the airborne transmission of aerosolised pathogens around the system, and potentially into the hospital building, through air movement and buoyancy effects.

Laboratory Investigations

At the heart of the work carried out by the PRoBE group is an adherence to excellence in data collection and a rigorous approach to both engineering modelling and microbiological analysis. Molecular techniques such as PCR are used to generate mathematical equations suitable for inclusion in a 1-D method of characteristics model, AIRNET, which is currently being updated to include an algorithm for the simulation of microbial transport on building drainage airstreams.

The work of the PRoBE group is gaining momentum and has contributed to providing solutions to difficult infection spread problems so far. We are hopeful and confident that the group can go on to add to the knowledge base we have started with the aim of providing improved public health for all buildings in the future.

Dr. Michael Gormley, November 2015


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Cutting Red Tape vs. Consumer Protection in Australia

High_Res_0234The Australian government is reviewing red tape and regulatory costs, whilst trying to protect the interest of consumers – an example of this is the WaterMark Certification System. This scheme is used to certify plumbing and drainage products, and materials used in water supply, sewerage, plumbing and drainage goods.

In 2014 a draft report reviewing the WaterMark Scheme was released to the public. The review was undertaken by the Australian Building Codes Board on behalf of the state and territory Building Ministers. This proposal is trying to reduce regulatory costs and red tape and the outcome from the public review was to assist in the decision regarding the future of the scheme. It is now clear that the original intent to deregulate has been revised, and some form of ongoing product scheme, modified or enhanced will be recommended.

The public response to the review was extensive, attracting 20 detailed submissions, all of which provided important contributions to the Board when considering recommended actions. The board concluded that some additional work was required to understand the economic benefits of making changes to the scheme.

The potential impacts of faulty water supply and drainage systems in buildings are well documented. The message from the industry is clear – any increased levels of deregulation will deliver risk, and any government contemplating to, or abrogating responsibility on issues of public health and safety, do so at extreme risk.

Some well documented known examples;

  • The cost of global Severe Acute Respiratory Syndrome (SARS) in 2003 was estimated at US$60 billion of business losses with very high mortality rates. This was driven from faulty plumbing systems mainly in China.
  • Eight deaths in Spain from more than 40 cases of Legionnaires’ disease.
  • A German Outbreak with two deaths and 60 cases hospitalized.
  • In Grimsby (UK) four people were diagnosed with Legionnaires’ disease.
  • In California three people who had stayed at a hotel in Ukiah were hospitalized from the hotels infected water supply.
  • In the Melbourne aquarium the case resulted in a number of deaths.
  • There are ongoing antibiotic-resistant bacteria infections in many Australian healthcare and aged care facilities and hospitals.

It is anticipated that a revised WaterMark scheme will be maintained as the only efficient means to deliver continuing consumer protection. The review highlighted that the scheme provides confidence and certainty to the market as product compliance targeted at consumer protection is able to safeguard health and safety. There is a clear expectation that protections for consumers have a basis in law.

Michael is a highly experienced certified practising accountant (CPA), Director of Studor Australia and Dyteqta Australasia. He sits on the board of several companies and is the president of the Parramatta Chamber of Commerce. Michael, Jim and Paul are the directors of the Parramatta based accounting firm ATB Partners, which was founded over 20 years ago. The successful firm is well known for its highly sought after tax consultants, financial advisors and business mentors.  ATB Partners specialises in providing advice to clients in retail, wholesale, manufacturing, professional services, franchise and construction amongst others. Please visit for more information.

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Plumbing Industry Insights from Australia

Michael Mekhitarian


This blog shares the insights of Michael Mekhitarian, director of Studor Australia Pty Ltd.  Michael is a highly experienced certified practising accountant (CPA), he sits on the board of several companies and is the president of the Parramatta Chamber of Commerce. Michael, Jim and Paul are the directors of the Parramatta based accounting firm ATB Partners, which was founded over 20 years ago. The successful firm is well known for its highly sought after tax consultants, financial advisors and business mentors. ATB Partners specialises in providing advice to clients in retail, wholesale, manufacturing, professional services, franchise and construction. Please visit for more information.


The plumbing industry is integral to the Australian economy. The reason for this is that pipes are used in every building in Australia. The services offered by the plumbing industry include the installation, repair and maintenance of pipes.

Industry Description

There are 50,250 plumbers in Australia and another 30,000 people that are employed within the industry across a variety of roles. The plumbing industry is highly fragmented with 25,250 businesses in Australia. There are many small contractors; 51% of businesses have no employees and 48% have between one and 19 employees. The average revenue is $514,851 and the average profit is $67,327. Profits accounts for 12.7% of revenue.

The industry is highly regulated with strict product and installation compliance requirements. Most plumbers focus on a narrow geographic area or a specialised service. There are some larger players in the market, however, their focus is on long term maintenance. Facilities management firms are expected to grow in the future as large long-term contracts across many trades are expected to increase.

Market Conditions

The industry has experienced variable demand conditions since the early 2000s. There has been solid growth over the past 5 years despite poor demand from most building markets. Industry revenue has increased annually by an average by 0.9% over the past 5 years to total $13 billion in revenue for this year. Demand from commercial building construction is expected to increase by 1.1% and new housing which is predicted to decrease by 1.7% this year. The low interest rates currently set by the Reserve Bank of Australia are expected to stimulate household spending and business expenditure.

In the past the global financial crisis has resulted in a decrease in demand from business and consumers. However, federal government economy stimulus resulted in an increased demand for plumbing services. The first home owner’s grant, the education construction stimulus and the solar hot-water systems government rebates have all resulted in steady growth for the industry. Regardless of government stimulus, the number of plumbing businesses contracted during 2012-13 by 3.4%. The withdrawal of government stimulus has had a negative impact on the industry.

Natural disaster relief provided by plumbers to the residents affected by the 2010-2011 Queensland floods provided a boost for the industry.

The market demand for plumbers is made up of 40% residential building companies, 30% non-residential builders and property managers, 20% households and residential property managers. The geographical distribution of plumbers mirrors the population and construction areas.

Internal Demands

Lower barriers to entry make it easy for new players to enter and leave the market. Competitive conditions have led to a decrease in margins. There is a skilled labour shortage with many businesses finding it hard to find additional skilled labour as many plumbers start their own businesses quickly after finishing their apprenticeships. Threats to the industry are easy to assemble plumbing fixtures that may restrict industry revenue growth.

To be successful in this industry you must have good cash management, an excellent reputation, offer a large range of services, have contacts within key markets and an ability to provide competitive tenders.

Revenue from plumbing activities is derived from the following activities: Water plumbing 30%, sanitary plumbing 24%, gas fitting 21.5%, mechanical plumbing 14.5%, drainage and roofing plumbing 10%.

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Approvals for the P.A.P.A. (Positive Air Pressure Attenuator)

The Studor P.A.P.A. was first brought to the markThe Studor P.A.P.A. Drainage Ventilation Technology. Air Admittance Valves. Drainage Systemset by Studor in 2003.

It had been invented by the late Professor John A. Swaffield and Dr David Campbell of Heriot-Watt University in Edinburgh, to resolve the problems of positive pressures (transients / back-pressure) within the drainage systems of multi-storey and high rise developments.

Prior to the research carried out at Heriot-Watt University which led to the invention of the P.A.P.A., there hadn’t been any studies carried out to define what positive transient pressures were. The last major plumbing study carried out was by Hunter (Hunter’s curve) in 1940, but as positive transient pressures had not been identified at that time, and were therefore unknown to him, he did not include this in his study.

On the whole, this lack of understaBuilding to the cloudsnding in the industry has led to very complicated and expensive drainage venting solutions, usually as a result of trial and error, with a standard building drainage design being adapted for installation in all different types of buildings without any scientific back-up.

With buildings being increasingly constructed higher and higher, with mixed use buildings and more complicated designs utilizing modern materials and methods, the industry is now starting to understand that it must look at ways to safely vent the drainage of these buildings.

Previous research by the Heriot-Watt University team had led to the development of the AIRNET computer program, which incorporates numerical modelling and allows for a drainage system of any size to be modelled, and venting arrangements assessed. This powerful software was central to the development of the Studor P.A.P.A., and provides the industry with the scientific back-up to support the viability of building drainage designs.

Our “Seeing is Believing” Test Tower, the topic of several other recent blogs, has enabled us to clearly show the industry what really happens in the drainage system, and why the Studor System* (incorporating the P.A.P.A. and Studor-manufactured AAVs) should be the preferred solution for the drainage systems of multi-storey buildings.

However, for many, this is not enough and this is where standards and approvals are critical. The Studor AAVs conform to numerous worldwide standards, but being a unique product, the P.A.P.A. was slightly more problematic. We have worked closely with international organisations, and continue to do so, to establish standards and approvals for devices which reduce the positive pressure within the drainage system, i.e. the P.A.P.A.

Australia: “Technical Specification for plumbing aP.A.P.A. Watermark - Watertecnd drainage products Part 463: Positive air pressure attenuator” was published in 2005, and the P.A.P.A. has held the Watermark approval (licence number WM-20006) since then. Every 2 years the Watermark licence is renewed after IAPMO has been satisfied that there has been no change to the product in production and that the relevant QA procedures and testing/performance requirements have been complied with.


 British Board of Agrément (BBA): BBALogoCertNo15_5224The BBA issued certificate number 15/5224 in June 2015. This provides verification that the P.A.P.A. has been independently assessed by the BBA as being fit-for-purpose. The application and renewal process involves laboratory tests, on-site evaluations, quality management checks and inspections of production. The key factors assessed and verified in relation to the P.A.P.A. were:

  • Drainage system design
  • Airtightness
  • Effect on water seals
  • Durability

– Local Authority Building Control (LABC): The Llabc_4890 Reg_RegDetailsABC issued certificate number EWWS493 dated July 2015. This verifies that LABC has independently checked the Studor System* (incorporating the P.A.P.A. and Studor-manufactured AAVs) for compliance in accordance with English and Welsh Building Regulations, and that it is also listed under the LABC Warranty scheme. When complete, the Scottish assessment will be added to the listing.

USA: “ASSE Standard #1030, Performance Requirements for Positive Pressure Reduction Devices for Sanitary Drainage Systems” was published in 2013, and the P.A.P.A. is currently undergoing intense review and testing by NSF.

This extensive coverage of approvals and recognition should provide anyone considering specifying or installing the Studor P.A.P.A. with full reassurance that it performs as stated, that its production is carried out in accordance with the highest of quality standards and that it is monitored by independent bodies.

For more information on the P.A.P.A. and/or the Studor System, please do not hesitate to contact us.

*marketed in the Middle East and the UK as the Terrain Pleura System

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Fun at the “Seeing is Believing” Test Tower!

Tony Hill

Tony Hill (our Technical Sales Engineer) talks to us here about some of his experiences at our “seeing is believing” test rig in the UK’s The National Lift Tower:

I was asked what the most fun thing was about being involved with the “Seeing is Believing” test tower. This is a difficult question to answer as there have been so many funny moments, so I’d like to share a few of them with you:

  • One of my colleagues, our Technical Sales DirectorBlocked toilet Daniel Rath, managed to block one of the toilets quite spectacularly by putting in 6 sausages, 2 metres of toilet paper, 5 handfuls of cat litter and 2 sanitary towels – he had to roll his sleeves up and put his hands in to mix it all around to clear it! This was just minutes after he’d been asked if he’d blocked a toilet in the testing so far, to which the answer was “no” – famous last words!
  • I was stood too close to the stub-stack WCThe National Lift Tower when we were testing the conventional vent pipe system on the second day and ended up with very wet trousers from water spitting out, much to the amusement of all of guests that day! I made sure I wasn’t so close the next time, but it did illustrate the poor performance of the conventional vent pipe system rather well!
  • The lift getting stuck on ground floor and having to walk up the fire escape to the press the reset button which is 127 meters up the tower. Three quarters of the way up, and slightly out of breath, I was told on the radio that it was working again. Oh well, I certainly got some exercise that day!
  • The very funny looks I was getting at the local supermarket getting the “flushing supplies” each morning!
  • Persuading Helen Williams, our OperationsHelen Williams Director, that she needed to wear a lot of safety gear and a harness to access the upper levels of the tower. Oh, and that the lift didn’t go all the way and that if the wind speed increased then the tower would rock and she’d have to go back down again. Despite the height she walked up/down clipping the harness onto the handrail she took all of it in good spirit, even when she found out that we’d secretly videoed her! I must confess that I’m a little scared of when that one might come back to bite me though!
  • Watching people’s faces as the solids hit the Bottom of the stackbottom of the stack and the delay before it was followed by the water coming down.
  • At the base of the stack, trying to spot what had been flushed down – prizes for the best guess!!!!!!!!!!!

Tony Hill
Technical Sales Engineer, Studor

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