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 EWW493 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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Low Cost From Medium to High Rise

The latest cost comparison study in Australia demonstrates that the Studor AU Cost ComparisonSystem is the most economical across all building heights

An independent study, commissioned by Studor Australia, has provided evidence that the Studor System, incorporating Studor AAVs (Air Admittance Valves) and Studor P.A.P.A.s (Positive Air Pressure Attenuators), is the most cost effective drainage system across all building heights, due to its reduced pipework requirements which result in a faster and easier installation process, in addition to the material savings.

The study compares the supply and installation costs of the Studor System against the other two main types of high rise sewer stack systems in use across Australia and New Zealand: a Reduced Velocity Aerator Stack System (RVASS) and a traditional passive vented system incorporating relief vents, also referred to as a Fully Vented Modified Stack System (FVMSS).

Whilst a previous comparison, based on an entire building project over 22 floors at Hamilton Harbour, demonstrated that the Studor System was the most cost effective for that size project, it also raised the question of how the stack systems would compare over shorter and taller building designs.

The new comparison compared the same three stack systems over several building heights. This time the calculations were based on a representative single stack using the three systems covering 8, 40, 70 and 90 floors.

Cost comparison image

An independent hydraulics consultant was commissioned to provide the design and bill of quantities. A separate consultant and estimator then provided a cost estimation for the bill of quantities with the aim of comparing the Studor System relative to an ordinary FVMSS and to two RVASS; one using 160mm and the other using 110mm pipework.

The results demonstrated that the Studor System is the most economical of the three drainage systems. The extent of the savings are typically over 40% against the RVASS systems and over 20% against the FVMSS system. Whilst the amount of saving differed depending on the building heights, the Studor System was the most cost effective for the four height options that were considered.

AU Cost Comparison - Percentage Savings

The Studor System offers additional benefits to just cost savings. The reduced pipework requirements offer a sustainable drainage solution, whilst the reduction in duct size required increases the habitable space available. In addition, site safety is improved with a reduced requirement for working at height, whilst the elimination of roof venting pipes and penetrations reduces thermal heat loss and enhances the aesthetic appearance of the building.

The full report providing more detail about the study, including a complete breakdown of all estimates, is available for download upon completion of this form.

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Studor Active Ventilation @ The National Lift Tower July 2015 Update

I can hardly believe it, but it’s now been 10 weeks since we launched our “Seeing is Believing” test rig – the past weeks have been an absolute flurry of activity! The response to our offer to visit the test tower and witness/participate in the testing has been overwhelming, on both a national and international level.

Test Tower Ready to Flush

Ready to Flush!

Our latest live demonstration event last week was attended by over 60 Public Health Engineers over 4 days, ranging from time-served to the newest batch of our future engineers. Also present to support me with running the event were Steve White (Studor Technical Director), Daniel Rath (Studor Technical Sales Director), Michael Chang (Studor Product Engineer) and Tom Gale (Studor General Assistant).

If you missed this event, then don’t worry – we will be back at the tower in September – and if you’d like to come up then please email me at

The results and reactions, even from those slightly “long in the tooth”(!), were all similar to the previous shows:

  • “Wow!”
  • “I think I have got it wrong in the past!”
  • “I’ll have to look at my designs more closely from now on!”
  • “I wouldn’t want to be sat on that, if that happens!” – this was specifically in response to witnessing the following video when 10 WCs were flushed with the Studor System isolated (with no venting).

Studor System Isolated – 10 WCs Flushing from Studor on Vimeo

Test Tower Supplies

Supplies for Flushing

During the hands-on testing, anyone attending will take an active role in the tests, from loading the WCs at the top of the stack, watching the AAVs working at the midway point, viewing the annular flow through clear sections of pipework, seeing the P.A.P.A. attenuating (slowing down) the positive transient and, at the base of the stack, witnessing the hydraulic jump and the speed of the solids against the delayed water flow. A member of the Studor team is available at all stages of the testing to answer any questions. What is a very important aspect of our events is that if anyone wishes to see one of the tests done in particular way, then we will do our utmost to accommodate any requests.


Actively vented shoes!

On a final note, one of our visitors last week misunderstood “active ventilation” and thought it related to her footwear – by far the best safety shoes so far on the test tower, although we have been advised that this is the safest nail varnish colour to have! :-)


Tony Hill at the base of the test tower


Tony Hill
Technical Sales Engineer, Studor
27 July, 2015

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Seeing is Believing!

Tony Hill


We asked Tony Hill (our Technical Sales Engineer) to answer a few questions about the “seeing is believing” test rig – the result of weeks of hard work by him and the team from Polypipe Terrain:


What is the purpose of the test tower, and what does it demonstrate?

Although the Studor System has been sold worldwide for over 10 years, one of the issues we’ve had when talking to various industry professionals is that they want to SEE evidence that the system works – of course, when its normally installed the drainage system is hidden within the infrastructure of the building, so it not accessible. The tower was the idea of a UK-based Senior M&E Manager, Les Copeland, and myself to clearly showTony Hill at the base of the test tower how the Studor System works in a real building. Given that we’re celebrating 40 years of Studor this year, it was an ideal opportunity to launch this project!

By utilising clear pipe and by having all of the P.A.P.A. units, AAVs and other fittings completely visible, it is a real way of demonstrating the occurrences within a real high rise drainage system and how they are managed by the Studor System versus a traditional vent system. The test tower has been very successful in illustrating that the Studor System out-performs the traditional vent system in maintaining the trap seals and protecting against the negative and positive pressures in the system.


Is it an interactive experience for you and the attendees?

Absolutely! Everyone who visits the test tower has the opportunityInteractive participation to take an active part in the testing and pushing the system to its limit. During the testing of the systems on the day it is very much a hands on test from all involved – the attendees add normal and abnormal items to the system (including sausages, burgers, toilet paper, cotton buds, wet wipes and sanitary products), as well as flushing the WCs. During the break-out discussions, the attendees are encouraged to give us their suggestions for different tests and scenarios which we try to accommodate. The results are showed via pressure monitors and U-gauges. It is very much a case of “seeing is believing”!

Is the test tower a world first?

Although not the first test tower for drainage, we believe it to be over 3 times the height of any existing test facility for drainage.

Why was the National Lift Tower a great choice of venue?

National Lift TowerWell, apart from the fabulous views at the top, the National Lift Tower is easily accessible from Studor’s UK office. Its central location in the UK means that it is also easily accessible for anyone visiting from the UK or flying into a UK airport. The fire escape shaft of the tower was effectively a dead space, with only an open steel framed staircase running from the bottom of the tower to the top. This means that all levels of the pipe work are accessible to view from a safe working platform. A great benefit was being able to fit 98m of straight pipework with the ability to change the pipework at anytime to bring in offsets, long runs, etc. As long as you don’t have a bad head for heights it is the perfect venue!

What skills do you have which helped with the implementation?

Before working for Studor, I have been a plumbing and drainage engineer on site and time-served as a mechanical building services engineer. This experience has given me a practical approach to installations and the problems that can occur throughout the whole process from drawing to installation.

Who was involved in the project?

The entire Studor team has been involved, providing support from the design stage right through to assisting with the show days. Our UK distributor of the IMG_6685Studor System (marketed as the Terrain Pleura System), Polypipe Terrain, also provided significant support with the design and installation. To cut down on the amount of on-site work, they prefabricated parts of the pipework before bringing it to the tower for installation. Of course, the team employed by the National Lift Tower have also been involved and have provided a great deal of support throughout the installation process and also on the show days. I’ve really enjoyed working with everyone on this project and it’s a great example of teamwork!

What have you learnt from this experience?

Personally I have learnt in a practical way about how air and air movement within the drainage is more important than the water flow. I have read in books and through my time at Studor about the facts and figures but “seeing is believing” is always the best!

 Who has attended so far?

IMG_2525As at the middle of June 2015 we have had 4 show days so far, which have been attended by a mixture of building regulation inspectors, consultants, designers, international developers, M&E contractors, main contractors and public health engineers. We’re planning more dates over the next year – please email me at if you’d like to attend.

How does the system educate us about active drainage ventilation?

In the show we can see with our live tests how active ventilation out-performs the standard designed and installed secondary vent pipe system and keeps the systems within a safe pressure zone to maintain the water trap seals. Look out for our future blogs in the coming weeks which will include additional detail and videos of the testing…

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National Women in Engineering Day Focus: Alex Keates

NWED - 23 JuneAlex Keats

Today we talk to Alex Keates, whose passion for machinery and how things are made drew her to engineering.

Since having studied in Bogotá (Colombia) and London (UK), her career path has led her to work as an Engineer for Hoare Lea in London.

Amongst other projects, she has been involved with an extensive property portfolio across Europe (shopping centres, hotels, etc.).

What’s the tallest building you’ve been involved with?

The Heron, also known as Milton Court, is a 36 storey 112m / 367 ft tall residential skyscraper in London. The building was developed by Heron International

What specific skills or attributes do you feel that women bring to engineering?

Analytical skills, different approaches to solve issues, and interpersonal skills.

Less than 10% of engineers in the UK are women. What advice or thoughts can you give to women thinking of studying or training to become engineers?

Be open minded but stick to the facts, ask many questions, believe in yourself and persevere.

What do you enjoy doing outside work?

Travelling, scuba diving, dancing and cooking.

What’s the funniest thing you’ve ever done?

Trying to explain a complicated technical issue to a client using a cooking / food analogy. The client had no idea of either, but was very interested, so I ended up explaining both topics, using my drawing and colouring in skills.

Anything you’d like to add?

We, men and women, need to be aware of our own strengths, abilities and limitations in order to complement and help each other out in all aspects of life.

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National Women in Engineering Day Focus: Elisa Bruno

NWED - 23 June

Elisa Bruno

Elisa Bruno’s passion for problem solving lead her to study for her MEng in Building Engineering and Architecture at the University of Catania (Italy), and for her MSc in Sustainable Construction Processes at the University IUAV of Venice (Italy).

She subsequently joined hurleypalmerflatt in July 2014, where she currently works in their London office as a Graduate Energy and Sustainability Consultant.

What’s the most notable project you’ve ever been involved with?

I had a hand in the Al Faisaliah retail mall refurbishment, a major scheme in Riyadh, Saudi Arabia. In fact, it’s currently the 3rd tallest building in Saudi Arabia.

What’s the tallest building you’ve been involved with?

After the Al Faisaliah, the tallest building I’ve been involved with was Swan Heights, Reading (UK) – a development which would have contained 352 apartments in three tower blocks of 28, 26 and 24 floors.

Are you a member of the Women’s Engineering Society (WES)?

Not yet, but willing to join soon!

What specific skills or attributes do you feel that women bring to engineering?

Intuition and a more holistic approach.

Less than 10% of engineers in the UK are women. What advice or thoughts can you give to women thinking of studying or training to become engineers?

Go for it! Engineering is great and you really feel you have the opportunity to make a difference in the real world!

What do you enjoy doing outside work?

I love travelling around the world, reading books and hanging out with friends!

What’s the funniest thing you’ve ever done?

That’s highly confidential, I’m afraid! :-)


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National Women in Engineering Day Focus: Alexandra Vella

NWED - 23 June

Alexandra Vella

Today’s spotlight is on Alexandra Vella, an Executive Engineer currently working for Hoare Lea in London.

It was her love of numbers/maths and physics and wanting to understand how things work which got her interested in engineering and led her to a career in Building Services.

What’s the most notable project you’ve ever been involved with and why?

I have been privileged to work on several landmark buildings, but the best was a grade 2* listed theatre in East London because the challenges were huge and it was so satisfying to see the final building in operation.

What’s the tallest building you’ve been involved with?

Falcon Wharf – a 19 floor landmark development, mainly residential apartments with mixed use, on the banks of the River Thames in London, adjacent to a heliport.

What specific skills or attributes do you feel that women bring to engineering?

Softer skills, intuition and empathy, a different logic (although we can think logically like men we do it in a different way).

Less than 10% of engineers in the UK are women. What advice or thoughts can you give to women thinking of studying or training to become engineers?

Engineering is a vast title which encompasses a massive variety of jobs. If you enjoy problem solving and working with numbers then you will find your niche in the engineering world. Lots of women are employed as engineers so you won’t be in a boy’s club.

What do you enjoy doing outside work?

Travel, socialising, rugby and volunteering.

What’s the funniest thing you’ve ever done?

Space planning plant rooms using an A0 plan and cut-out plant shapes with blue tack on the back to figure out the plant arrangement!

Anything you’d like to add?

There is a big push for women to get involved in engineering which is a good thing, but I am concerned that this does not achieve what it set out to do, which is to encourage a better mix of men and women. I am involved with the IET women’s group and have many female friends in my company and industry who serve as sounding boards and role models. However, I would be keen to see more mixed events which are representative of the wider industry, just so women considering becoming engineers don’t get the wrong impression.

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National Women in Engineering Day Focus: Amanda Stanley

NWED - 23 JuneAmanda Stanley

Amanda Stanley is a Senior Public Health Engineer for hurleypalmerflatt in London’s West End.

Back in her school years she loved Technical Drawing and then “just happened to fall into a job doing plumbing and not graphic design, but [she’s] not [looked] back since”!

She is now very well known and well respected in the industry.

What’s the most notable project you’ve ever been involved with and why?

Marble Arch Place – mixed use development
18 storey luxury apartments
8 storey commercial offices
Ground and lower ground floor retail and building entrances
5 basement levels with cinema, residential amenities, FM amenities and Landlord areas including car parking

What’s the tallest building you’ve been involved with?

Principal Tower – 55 storeys above ground floor residential high rise in Principal Place, Shoreditch, London.

What specific skills or attributes do you feel that women bring to engineering?

Common sense/different way of thinking.

 Less than 10% of engineers in the UK are women. What advice or thoughts can you give to women thinking of studying or training to become engineers?

When you spend a quantity of time designing a project and seeing the development fully through to the final product is very rewarding.

What do you enjoy doing outside work?

Spending time with my family.

What’s the funniest thing you’ve ever done?

When I was on a Christmas party and the ‘gents’ all decided to get me drunk, but I was still standing whilst they were all still trying to find their feet after 14 rums, 2 vodkas, 4 red wines, 2 tequilas and 1 pint of shandy. Luckily I do not drink now!

Anything you’d like to add?

I know there is not another job I would love as much and each day is different with never the same problems, solutions etc.

I’ve been an engineer since I left school at 16 and 30 years later I would not change a thing. Well, maybe the time at college and paperwork!!! Just kidding.

I am currently looking into patenting a product I’ve developed, which is very exciting.

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National Women in Engineering Day Focus: Professor Lynne Jack

NWED - 23 JuneProfessor Lynne Jack

Professor Lynne Jack (Professor of Building Services Engineering) is Director of the Centre of Excellence in Sustainable Building Design) at Heriot-Watt University in Edinburgh, Scotland.

What got you interested in engineering?

I first became interested in engineering during my time at secondary school. I remember being intrigued by the concept of engineering principles applied to the development of renewable energy technologies. Studying for my undergraduate degree in Energy Engineering cemented my desire to work in the field, as I could see how the knowledge gained and skills learned could be applied to real-world challenges.

Where did you study?

I completed my first degree at Edinburgh Napier University in 1990, and my PhD at Heriot Watt University in 1997.

My first degree was in Energy Engineering and, after graduation, I worked as a Thermal Engineer on the cooling design of electronic circuit-boards. After spending some time working for a small engineering consultancy, I then joined Heriot-Watt University where I began my research career working in the area of water and drainage systems for buildings.

What’s the most notable project you’ve ever been involved with and why?

Almost every project is different so it’s always difficult identify the most notable. But those that have a tangible outcome or where academic impact on the sector can be demonstrated are usually the most noteworthy. Personally, I enjoy site monitoring or measuring data from experimental test-rigs, and using this to develop simulation models to predict system performance. Examples of notable site investigations include data gathered from social housing apartments in Scotland and from an experimental test tower in Taiwan.

Projects where we have collaborated with industry partners have also been hugely successful and, I believe, present the best opportunity for ensuring impact from academic research. Examples includes our very successful relationship with Studor, where we have, over an extended period of time, built increasingly sophisticated simulation models to predict the performance of systems and products for building drainage, and also the LUNA project work, where we are about to embark upon a study of the impact of water efficiency upon the viability of the loading units methodology to pipe and pump sizing for water supply systems in buildings.

What specific skills or attributes do you feel that women bring to engineering?

In my experience, the best engineers have demonstrated a genuine ‘can-do’ attitude, and have been open to team-working and interdisciplinary collaboration. The very nature of engineering challenges means that, oftentimes, the way to tackle a particular challenge, problem or design is not immediately obvious, but working together and being open to ideas will, more often than not, allow the team to reach the optimal solution.

Less than 10% of engineers in the UK are women. What advice or thoughts can you give to women thinking of studying or training to become engineers?

My advice to those thinking of studying or training to become engineers is to remember that the rewards always outweigh the challenges! Study hard, work hard and try to look out for examples of good practice from people that you’d like to emulate. And try to think of yourself not as a female engineer but as good engineer, able to deliver to the highest standards of quality in response to the requirements of a job.

What do you enjoy doing outside work?

Married with two teenage sons, I dedicate most of my time outside work to my family. In rare moments to myself, I enjoy reading music, some cycling and am currently learning a new language (albeit rather slowly!)


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