cb1234b6616be17542896d4f51fc45b0eb04d7fb

Sunday, September 29, 2013

The Romans - Part 2 - The Original Master Builders

I just wonder if the modern buildings that we are currently constructing will leave a similar legacy to that of the Romans. If we can make the same positive impact that the Romans made to the built environment then we will leave behind a similar positive lasting legacy for our future generations

Source: http://en.wikipedia.org/
In last week’s article I demonstrated how the Roman occupation of the UK left a lasting impression on our built environment and how the introduction of new building techniques allowed larger, bolder buildings to appear, the like of which had never been seen before in the UK. I also explained that the location of towns and cities was carefully planned to make optimum use of the natural resources available in a particular location, and how gravity was used to provide fresh flowing water into towns and cities often using lead pipes, sometimes over great distances incorporating aqueducts which made use of masonry constructed arches.  For the rich and important in Roman society their homes and other buildings became status symbols. The size of the building, the inclusion of mosaics and painted plastered walls, under floor heating and fresh running water would demonstrate how rich and powerful the occupants were. 

If you ever watch programmes such as Time Team (for those who do not know, this is a TV programme where Archaeologists, Geo-Technical Engineers and Historians have three days to unearth and re-construct a particular building/structure), you will see that there is always a great deal of excitement when they suspect they have unearthed a mosaic.  The reason for the excitement is because this will often tell the Archaeologists that they have found a significant or high status building.  Mosaics were usually constructed within floors however wall mosaics were also used.  Making an elaborate mosaic was a task that would require the skills of a master mosaic craftsman would set out the picture/design while others would complete the actual work of making the mosaic.  Small pieces of stone or clay would be used to create the image of the mosaic which would often depict a historical event, have a cultural or spiritual meaning, possibly depict an animal or even be an elaborate geometric design. Some of the best examples of Roman mosaics in the UK can be seen at Fishbourne Palace in West Sussex (see image at the beginning of this article), where Archaeologists discovered a number of elaborate mosaics which they have dated back to AD75 – 80, making them the oldest discovered mosaics in the UK. The mosaics at Fishbourne Palace provide a good insight into the skill that would have been necessary (to design and construct), remember over nearly 2000 years ago, to produce such elaborate designs.

Roman Atrium - Ephesus - Source:http://www.highonadventure.com
Larger Roman houses were designed around a central atrium.  You can see from the image that a Roman atrium would have no roof and would therefore be open to the elements.  A recess or trough would be built into floor which would collect rainwater, which would be used for many different things including drinking and washing.  You could say that this is an early form of rainwater harvesting!, something that is becoming increasingly popular today.  Various rooms would then be designed directly off the atrium for which the amount and use of the rooms would depend on the size and status of the buildings.  Larger villas/houses would incorporate a second atrium, something referred to as a Peristylium, which would include a garden area and would also be designed to have rooms accessed directly off it.  The orientation of the building would be designed so that Peristylium would be able to catch as much sun as possible (south facing), however for comfort, in warm weather the courtyard would also incorporate trees to provide much needed shade.


Arguably, one of the most innovative ‘inventions’ that was introduced by the Romans was under floor heating.  It is staggering to believe that this would have been possible at the time however palaces, bath houses and high status buildings would often incorporate under floor heating, which was provided by a system know as a hypocaust.  A hypocaust comprised a raised floor which would typically incorporate a two foot (600mm), void underneath.  The void would be created by the stone floor surface being supported off pedestals (small columns).  Heat was then be introduced into the void by a furnace, where a person (usually a slave) would ensure that a fire was continually burning.  As the heat would built in the floor void the stones forming the floor surface would start to absorb this heat, which through conduction would eventually increase the temperature at the floor surface, this would heat the rest of the room as well as the floor. Furnaces were reasonably large and therefore took up a lot of space so the Romans usually designed these to be out of sight and therefore located them in an adjoining room.

Roman hollow box tiles - Source: http://www.thenovium.org
The Romans were so ingenious they even thought about ventilation!  As you would image the furnaces used for the hypocaust system would also create a lot of smoke/fumes, which needed to be directed away from the internal spaces. The Romans dealt with this by building spaces into walls, known as flues, to provide a safe path for escaping smoke and fumes.  Excavations at Ashtead Villa in Surrey revealed that the Romans used box flues to vent hypocaust systems. ‘Box-flues are hollow box-like tiles set into walls to allow hot air from an under floor hypocaust to heat the room walls' Source: http://www.thenovium.org

There is no doubt that Roman Architecture and Roman Engineering was well ahead of its time, evidenced by the vast array of buildings and structures that still exist today in many parts of the World.  Within this and last week’s article I have briefly discussed a small number of Roman techniques such as rainwater harvesting, the use of mortar, the use of arches, under floor heating, ventilation etc. for which although technology has developed, these are still used extensively today. I just wonder if the modern buildings that we are currently constructing will leave a similar legacy. If the earth still exists in 2000 years (a completely separate discussion!), what conclusions will the people of that time draw about us and the built environment we are creating now? If we can make the same positive impact that the Romans made to the built environment then we will leave behind a similar positive lasting legacy for our future generations.  I suspect however that very little of the World we are creating today will remain compared proportionally to the amount of Roman remains that exist today.  This really tells its own story.  If I am around in 2000 years I will be more than happy to be proved wrong! 

Please feel free to share this article and other articles on this site with friends, family and colleagues who you think would be interested

Information/opinions posted on this site are the personal views of the author and should not be relied upon by any person or any third party without first seeking further professional advice. Also, please scroll down and read the copyright notice at the end of the blog. 

Monday, September 23, 2013

The Romans - The Original Master Builders - Part 1

There was nothing random about the location of Roman villages and towns. Even before construction would commence the Romans would carefully select where towns and villages would be sited. These were carefully planned to make optimum use of natural resources such as food, water, timber, stone etc. in a particular location

Source: http://azelina.wordpress.com
One of the wonderful things about living in the UK is our diverse history and what this history has been left behind as a reminder of different historical period.  This is no better demonstrated than in our built environment where there exists many wonderful buildings/structures that provide us with an insight into bygone cultures, politics, classes, lifestyles, technologies and the like.  It is only by looking at our historic built environment that we can fully appreciate the skills and ingenuity of the people of their time. Our predecessors would not have had access to modern building equipment and modern techniques that are available today. Nowadays with the use of things like digital laser measuring equipment and off site manufacturing we are able to work to high levels of accuracy allowing us to design to extremely tight tolerances, something I am sure our predecessors would never have ever dreamed of.  Therefore, next time you look at an older buildings, possibly a heritage building, just take a few moments to appreciate the skill, ingenuity and blood and sweat that would have been necessary at the time of construction in order for the building to be robust enough to be standing, often hundreds or even thousands of years, after completion.

Source: http://www.bible-history.com/maps/06-roman-empire.html
From a built environment point of view in the UK, a significant period in history was from circa 43AD to 410AD, which is when the Romans occupied large parts of the UK as well as most of mainland Europe, part of North Africa and parts of the Middle East.  At the time the Romans were extremely powerful and were able to take occupation of pretty much anywhere they wanted due to their superior military skills and power.  The Romans brought with them technical skills and building techniques never seen before in the UK.  This allowed them to stamp a lasting mark on the UK, one which the large amounts of remaining Roman buildings, structures, roads and remains bare testimony too even today, nearly 2500 years after they were first built! 

Firstly, let me dispel a myth - most would associate Roman buildings as large masonry constructed villas, with painted plastered walls, mosaic floors and running water etc. This is largely down to the media as when a film or documentary about the Romans is broadcast, this is what is usually portrayed, however these larger masonry structures were inhabited primarily by the rich and powerful, and the reality was that most people during the Roman occupation lived in timber constructed buildings similar to the Celts who preceded them.  It is from the larger masonry villas and structures that more advanced building techniques were introduced into the UK.

There was nothing random about the location of Roman villages and towns. Even before construction would commence the Romans would carefully select where towns and villages would be sited. These were carefully planned to make optimum use of natural resources such as food, water, timber, stone etc. in a particular location.  Security was also a key consideration where the Romans would ensure that the location and orientation of their towns and villages provided a secure environment as possible for those who would occupy these settlements. Early Roman towns were fortified around their perimeter with an earth ramp (embankment) and a wooden fence, however these were replaced in and around the 3rdcentury with much more robust stone walls, towers and gates.

The Colosseum - Source: http://www.telegraph.co.uk
Prior to the invasion of the UK, the Romans had spent hundreds of years building large, bold palaces, temples, bath houses and elaborate towns and cities throughout their ever expanding empire. The jewel in the crown was Rome itself which boasted buildings such as the Colosseum (completed circa 80 AD), the original St. Peter’s Basillica (completed circa 349 AD) and the Pantheon (completed circa 125 AD).  These types of buildings demonstrated that the Romans had exceptional architectural and engineering skills, the like of which had never been seen before in the UK.

Larger buildings started to emerge in the UK where the Romans introduced limestone mortar which comprised of a mixture of lime, sand, gravel and water, to bind stones together to form walls, arches and vaults.  Other mixtures were used to form mortar depending upon available raw materials in a particular location, however when set the completed wall/structure would be extremely strong and durable, which is evident from the many remaining Roman buildings and remains that still exist today.

Sanitation was also a priority as the Romans realised the importance of hygiene in reducing illness and death in the general population. Running water, drains and sewers were therefore considered as important during the planning of Roman towns and cities.  Gravity was a great ‘asset’ which the Romans would use to channel water from springs and other natural water courses, sometimes over considerable distances.  This emphasises the earlier point that the Romans were meticulous in planning of the location of towns and cities to ensure that they would have a watercourse close by which was at a height (level) which would allow them to use gravity as a natural transporter of fresh water.
In next week’s article I will discuss Roman buildings in more depth and demonstrate how the Romans incorporated under floor heating into their palaces and bath houses, how the Romans included plastered and painted walls and how mosaics were used as status symbols by the rich and famous. 

Please feel free to share this article and other articles on this site with friends, family and colleagues who you think would be interested

Information/opinions posted on this site are the personal views of the author and should not be relied upon by any person or any third party without first seeking further professional advice. Also, please scroll down and read the copyright notice at the end of the blog.

Monday, September 16, 2013

Lean Construction – Can the Construction Industry learn from lean processes in the Manufacturing Industry?

Guest article from Richard Davies Project  Manager Capital Projects Property Services – Severn Trent Water 

In the current economic climate with clients having to justify value and contractors fighting an ever decreasing margin, the drive towards a leaner, more efficient way of working is inevitable and to disregard Lean is to remain left behind

Source: http://www.constructioncitizen.com
Earlier in the year a few colleagues and myself took a couple of hours out to take a tour around the Jaguar factory at Erdington, just outside Birmingham.  It is a fantastic example of how an organisation has taken Lean manufacturing and pushed it into every element of their process.  The result is quite staggering, a logistics process that delivers parts just in time, minimal waste, a workforce who take pride in their work and most importantly a competitive end product of brilliant quality. The purpose of the trip was to see Lean manufacturing in practice and to establish which elements, if any could be used in our organisation to improve the way we work.

The first, somewhat cynical reaction, is to say it’s all very interesting, but it isn’t relevant to construction work.  After all it is a production line and they have two very important key components, - they are making virtually the same thing time after time and they have a relatively stable work load so they can organise themselves to maximise efficiencies.  The workload in construction is so fluid and so varied it can’t possibly work. Indeed it may be difficult to apply it wholesale as two projects are rarely similar, due to procurement route, client type, client priorities etc, but to disregard all of the philosophies as irrelevant would be to miss a huge opportunity for the industry and to allow clients to squeeze every last percentage of value from a project.  What is a construction project if not a series of processors?

Source: http://www.walshgroup.com
One of the key traits that was evident from the visit was the level of accountability held by the operatives on the shop floor.  They knew exactly what was expected, the quality they were to deliver and the timeframe they were to deliver to.  If one operative was falling behind, there was a chain to pull and others on the same workstation pulled together to complete the task and catch up.   If their work fell below the required standard for any particular reason, other than mechanical failure, an element of ‘refocussing’ would be called for by the management.  By cascading this level of accountability and responsibility, Jaguar were able to remove two or three levels of interim management and crucially increased the level of pride the workforce had in their work.  If only all tradesman within a construction project had similar levels of pride in their work.  So often when walking round a project half way through, there are examples of tradesmen not respecting others work for example plumber completing a second fix in a toilet but not protecting the new floor covering that has been laid.  Alternatively it may be a site operative disposing of a coffee cup or sandwich wrapper behind stud wall or bulkhead which will be covered up.  Whilst this does not necessarily affect the final visual impact, it is evidence of the mentality of some of the people in the industry.   

All of this leads to arguments as to whose responsibility it is to co-ordinate teams to eliminate re-working which results in disputes and higher costs for all.  Contractors may well point at the clients for trying to drive down costs, but they must bear a responsibility for providing a sufficient cost to complete the works properly.  Maybe if the industry could instil the level of accountability in the supply chain as Jaguar do it may go some way to resolving the issue. The other major items are the commitment to improve, whatever the percentage in efficiency and a ruthless drive to minimise waste.  There is no excuse for saving a single percent, simply because it is only 1%.  During the value engineering exercises undertaken on projects, the temptation is to target the areas of prime expenditure as this is where you can usually make the biggest saving for the least effort or the biggest bang for the buck so to speak.  However in this exercise sometimes the smaller items get lost as not worth the effort which leads to many missed opportunities to really drive value down every element of the project.  

In addition, every process at Jaguar is broken down and analysed to identify the components that add no value and are therefore waste.  These are then removed from the process.  If this philosophy was adopted on construction sites it would be revolutionary – all those trips to a skip, all that re-working because the electrician hadn’t finished before the ceiling fitters were in, the possibilities are endless.

In the current economic climate with clients having to justify value and contractors fighting an ever decreasing margin, the drive towards a leaner, more efficient way of working is inevitable and to disregard Lean is to remain left behind.

Please feel free to share this article and other articles on this site with friends, family and colleagues who you think would be interested

Information/opinions posted on this site are the personal views of the author and should not be relied upon by any person or any third party without first seeking further professional advice. Also, please scroll down and read the copyright notice at the end of the blog.

Monday, September 9, 2013

Housing Health & Safety - Part 2 - How to carry out a Housing Health & Safety Rating System (HHSRS) Assessment

The inspector is required to undertake what is fundamentally a risk assessment of  29 different hazards and quantify this by calculating a score for each hazard.  Therefore a house could actually have 29 different scores.  A common misconception with HHSRS is that a single score is calculated for each dwelling

Source: http://blogs.aldermoorfarm.coventry.sch.uk
In last week’s article I discussed health & safety in the home and in particular the way in which habitation and health & safety issues were assessed under the former fitness standard.  The article identified why the fitness standard was limited in its scope and how this has now been addressed since the introduction of the Housing Health & Safety Rating System (HHSRS) in 2006.  

When an inspection is made under HHSRS, usually by an Environmental Health Officer or a Building Surveyor, the inspection will consider a wide range of potential hazards under 29 different categories, which are divided into four main groups:

Physiological requirements
Psychological requirements
Protection against infection
Protection against accidents
·         Damp and mould growth
·         Excess cold
·         Excess heat
·         Asbestos and manufactured mineral fibre
·         Biocides
·         Carbon monoxide and fuel combustion products
·         Lead
·         Radiation
·         Uncombusted fuel gas
·         Volatile organic compounds

·         Crowding and space
·         Entry by intruders
·         Lighting
·         Noise
·         Domestic hygiene, pests and refuse
·         Food safety
·         Personal hygiene, sanitation and drainage
·         Water supply for domestic purpose

·         Falls associated with baths
·         Falling on level surfaces
·         Falling associated with stairs and steps
·         Falling between levels
·         Electrical hazards
·         Fire
·         Flames and hot surfaces
·         Collision and entrapment
·         Explosions
·         Position and operability of amenities
·         Structural collapse and failing elements

The inspector is required to undertake what is fundamentally a risk assessment of each of the 29 different hazards and quantify this by calculating a score for each hazard.  Therefore a house could actually have 29 different scores (although this is unlikely as hazards would need to be identified for every category for this to happen).  A common misconception with HHSRS is that a single score is calculated for each dwelling, which is completely incorrect. By looking at the scope of the 29 categories it is clear to see how comprehensive the assessment is compared to the fitness standard (see last week's article) and although habitation issues are still included, a HHSRS assessment considers much wider health & safety issues that will impact on those occupying/visiting a dwelling.  

In order to arrive at a score for each hazard the inspector firstly needs to have a good knowledge of the rating system and how it works.  This requires an understanding of what to look for/at under each hazard, an appreciation of how serious an issue may be, which will include an assessment of the likeliness of the hazard occurring and also an understanding of the seriousness of the hazard should it occur.  This demonstrates that an inspection is much more than identifying hazards/issues, it is also about considering the likelihood and impact as well, which is not an exact science.  When HHSRS was first introduced and prior to undertaking the pilot surveys I discussed in my previous article I remember spending a great deal of time reading the guidance produced by the Department of the Deputy Prime Minister (now the Department of Communities and Local Government), which I have to say is very good and well worth a read if you are unfamiliar with HHSRS (Link).

Source:http://www.goodfieldconsulting.co.uk/risk-assessment/
The inspection itself is very different to anything that I had undertaken previously as a Building Surveyor.  To demonstrate how a hazard is assessed and how a score is calculated I will use the example of the potential for someone to fall out of a window.  This could be due to serious disrepair, inappropriate glazing, lack of sufficient guarding, damage or missing restrictors etc. It is important to note that this is something that would not have been considered under the fitness standard. Let us assume that the window in question is within the first floor bedroom of a typical two storey dwelling.  As with all risk assessment processes there needs to be an assessment of likelihood and severity. 

Likelihood - Firstly, the inspector must ask themselves how likely is it that the hazard will occur? This will depend on a number of factors such as the severity of disrepair, location, where in the room the window is located etc. Likelihood is expressed as a ratio and is the subjective opinion of the inspector, based upon the evidence he/she sees at the time of inspection.  So, there will be a greater likelihood of a hazard occurring if a window is in serious disrepair, with damaged glazing which is located in a position that someone could fall onto it, compared with a window with minor disrepair and at a height that it would be more difficult for someone to fall onto it.  This demonstrates two possibilities under the same HHSRS hazard, but each posing a different likelihood of occurring.  In the first instance the inspector may decide on a 1 in 10 likelihood of the hazard being realised and in the second the inspector may decide there is a much lower likelihood and allocate a ratio of 1 in 100.  There is no exact science to this however the assessment allows the hazard to be quantified.

Severity – Next the inspector must ask themselves, if the hazard is realised how serious will the consequences actually be?  HHSRS refers to this as the ‘Spread of Harms’.  A great deal of research was carried out during the development of HHSRS and part of this involved the production of data from accident statistics and input from organisations such as The Royal Society for the Prevention of Accidents (RoSPA). This enabled the significance of hazard outcomes to be defined (HHSRS allocated classes – see below) and subsequently allowed these to be quantified for score calculation purposes. For example, research data showed that for every 100 people who have turned up in hospital Accident and Emergency departments, from information collected, it can be show (for each hazard) that: 

W% will be dead
Class I
X%  will have broken several bones and will be in traction for some months
Class II
Y%  will be patched up and referred to outpatients   
Class III
Z%  will be told to go home and take an aspirin
Class IV

To avoid confusion HHSRS also defines each of the classes above to provide consistency during the inspection and assessment process and for the score calculation process. Each of the four classes are weighted to reflect the significance of the potential harm:

HHSRS  - Spread of harms definitions:


Class I – Extreme 
Death, permanent paralysis below the neck, malignant lung cancer, regular severe pneumonia, permanent loss of consciousness, and 80% burn injuries.

Weighting 10,000
Class II – Severe
Chronic confusion, mild strokes, regular severe fever, loss of a hand or foot, serious fractures, very serious burns and loss of consciousness for days.

Weighting 1,000
Class III -  Serious
Chronic severe stress, mild heart attack, regular and persistent dermatitis, malignant but treatable skin cancer, loss of a finger, fractured skull, severe concussion, serious puncture wounds to head or body, severe burns to hands, serious strain or sprain injuries and regular and severe migraine.

Weighting 300
Class IV – Moderate
Occasional severe discomfort, chronic or regular skin irritation, benign tumours, occasional mild pneumonia, a broken finger, sprained hip, slight concussion, moderate cuts to face or body, severe bruising to body, 10% burns and regular serious coughs or colds.

Weighting 10


For some situations there may be one likely outcome, but for most there could be a number of possible outcomes, in terms of the level of harm, so the spread of harms could cross all four separate classes. For example, falling out of a window on the 80thfloor of a block of flats would provide only one outcome – death (So class 1 would be 100% and classes II, III & IV would each be 0%), however falling out of a second floor window might give a range of possible outcomes, giving a figure (percentage) across each of the four classes of harm.

Once the inspector has decided on the likelihood and established the spread of harms (available from HHSRS guidance, within each hazard) it is then finally possible to calculate a score.  This is done by dividing the weighting of each harm class by the likelihood and multiplying by the spread of harms.  I know this is confusing so it more easily demonstrated by using our example of someone falling out of a first floor bedroom window, in the first instance let’s assume that the likelihood is low:

Class
Class of harm weightings

Likelihood
1 in

Spread of Harms

Total
I
10,000
÷
500
x
0.2
=
4
II
1,000
÷
500
x
1.6
=
3.2
III
300
÷
500
x
7.9
=
4.74
IV
10
÷
500
x
90.3
=
1.81
                                                                                                                          Total        13.75 (14)

As you can see the score calculation of 14 is low, but see what happens to the hazard score below if the issue is more serious and the inspector thinks there is a much greater likelihood: 

Class
Class of harm weightings

Likelihood
1 in

Spread of Harms

Total
I
10,000
÷
5
x
0.2
=
400
II
1,000
÷
5
x
1.6
=
320
III
300
÷
5
x
7.9
=
474
IV
10
÷
5
x
90.3
=
180.6
                                                                                                                     Total     1374.6 (1375)

Nowadays there are spreadsheets as well as various mobile technology applications, with built in spread of harms data for each hazard, which will do these calculations with only minimum input necessary from the inspector.  Having said that I would not let any of my Surveyors undertake these types of assessments without understanding the method explained above first.  This is important to help them understand the significance of each hazard as well as trying to achieve consistency between inspectors.  Remember, the assessment is the opinion of one individual and therefore subjective.

Once scores have been calculated for HHSRS categories’ each hazard into a category 1 or a category 2 hazard:

Band
Hazard Score
A
5000 or higher
B
2000 to 4999
C
1000 to 1999
D
500 to 999
E
200 to 499
F
100 to 199
G
50 to 99
H
20 to 49
I
10 to 19
J
9 or less

Any hazard identified with a score of 1000 or above will fall within band A, B or C (depending on the score), and is classified as a Category 1 hazard.  The existence of a Category 1 hazard will invoke compulsory Enforcement Action by the Local Authority if not dealt with urgently.  Also, category 2 hazards should not be ignored and steps should be taken to eliminate, reduce or manage these hazards as well.

In order to explain the system, discuss the assessment process and cover score calculation, this article is a little longer than my usual articles.  This was necessary in order to cover some of the key points in what at face value can seem to be a complicated system.  Hopefully, I have provided an appreciation of the different mindset that is required by an inspector and demonstrated that these assessments should only be carried out by those who have the right level of knowledge and understanding of the system and how it works.

Please feel free to share this article and other articles on this site with friends, family and colleagues who you think would be interested

Information/opinions posted on this site are the personal views of the author and should not be relied upon by any person or any third party without first seeking further professional advice. Also, please scroll down and read the copyright notice at the end of the blog.