Merry Christmas and Happy New Year !

Dear readers,

it filled me with joy to see that my writings are appealing to readers all over the world: from Belgium to Malaysia and Brazil, from the US to Russia. I wish all of you a Merry Christmas and a Happy New Year !

Kind Regards,
Peggy

Explaining BouwData - part 8

Long time since I found time to write something on this blog. I still don't have a lot of time but sometimes one just has to create some :o)

Anyway, concerning BouwData: so far I explained the way the contractor looks at an estimation (material code) and the way the designer does (object code). As stated in one of my earliest writings on this blog, there is also a third party who has an interest in estimating: the owner or developper. For them there is the development code.

What is important to developpers ? m² floorspace ! 
And moreover: how many square meters is needed for construction ? And of the net floor space which remains, how much of it can be sold to clients in case of apartments or how much can be used for e.g. beds in a hospital ?

Again I looked for standards to help me out. In Belgium and the Netherlands we have a standard on how to measure surfaces : NBN B06-002 which is equal to the NEN 2630. The latter one is already replaced by the NEN 2580 when they defined the "Bouwbesluit". 
In Germany there is the DIN 277 and there is also an ISO 9836 available.

In 2011 the EN 15221-6 came to life but this is a standard for facility management. In the Netherlands a commission stated that this is an entirely different business, so they hold on to their NEN 2580. And in Belgium ... well, here it is business as usual: every organisation defines his own way of measuring :o)

What do I do ? The NBN B06-002 is quite simple and resembles a lot the NEN 2580, DIN 277 and ISO 9836. So I stick to that.

In this blog some practical guidelines in a nutshell.


Gross Floor Area
in Dutch: Bruto Vloeroppervlakte (BVO)
in DIN 277 indicated by BGF

According to the NBN B06-002 you have to count the gross floor area on all levels. Thus also the levels partially or entirely underground, technical levels, roof terraces and attics where you can do something. You measure along the outer side of the facade on each floor just above the floor finishing. 

Staircases, elevators and technical shafts, all belong to the BVO.

What doesn't belong to the BVO ?

• smaller parts with a section < 0,5m² on the outside of the facade
• free standing columns outside the facade with a section < 0,5m²
• voides with a surface > 4m²
• basements with a free height < 1,50m
• roof surfaces who are not used as a terrace
• open staircases outside the building
• non covered area's such as patio's with a surface > 4m²
• metallic gangways along the facade with maintenance as its single purpose

This is the same as in the DIN 277. 
In the ISO 9836 this is the "total floor area". This standard makes a distinction between spaces who are totally surrounded by walls and spaces who are partially open to the surrounding area. The NEN 2580 makes even a further distinction between covered outside spaces and non-covered outside spaces, both when adjacent to the building. We don't look at gardens or sitting areas which are detached from the building.

Personally I make the distinction by adding an "e" to BVO for exterior when I measure terrraces and balconies and adding an "i" for interior when measuring entirely closed rooms/buildings.

When your building has a common wall with its neighbour, you measure to the heartline of it.

Net Floor Area
in Dutch: Netto Vloeroppervlakte (NVO)
in DIN 277 indicated by NGF

In short the net floor area is the gross floor area minus solid construction elements.

Following items are to be left out of the measurement:

• walls
  when you take all the walls out of the measurement, you speak of net floor area
  when you take only the bearing walls out, you speak of used floor area
  in Dutch the latter one is called "gebruiksoppervlakte" and marked by GO  
• voides with a surface > 4m² 
• parts of the room where the free height is < 1,5m
  remark: in the DIN 277 these parts do belong to the net floor area 
• free standing column or a small wall when the groundsurface > 0,5m² 
• shafts for technical ducts when the groundsurface > 0,5m²

Incidental alcoves on the outer walls with a groundsurface < 0,5m² are ignored.


Defined spaces and functions

In Belgium, every architect, creates names for the different spaces in a building. Sometimes he or she is consistent over all his/her projects, sometimes they like to invent names for every new project.

One could look at column 9 of table 0 of the SfB to define spaces but again, as with table 2 and 3 for the material code, I found the names in the Dutch "Bouwbesluit" more related to daily practice.

The DIN 277 roughly devides the net floor surface into:

• usefull surface
• technical spaces
• spaces for traffic
• rest surface (with the free height < 1,5m)

The Dutch "Bouwbesluit" is slightly different. 
They defined following spaces:

1 toilet
2 bathroom
3 technical spaces
4 spaces for traffic
5 storage of bicycles
6 storage of garbage
7 elevator shafts
8 space used by people
9 undefined space (is the same as the "rest surface" of the DIN 277)

Next to defined spaces they have defined functions for the use of spaces:

1 living
2 meeting
3 captivity
4 health
5 industry
6 office
7 lodging
8 education
9 sports
10 shopping
11 other functions where people are not constantly present



Development Code

So, how do I glue this and other questions concerning floor surfaces together into one code ?

When I receive a plan in a design & build project, I first check the terrein surface. Believe it or not but it happened that a part of the building was designed on the ground of the neighbour !

The total terrain surface (TO) can be devided into categories and is to be marked on a plan:

• surface to be build on (BTO - red), measured according the NBN B06-002
• surface to become a garden (ATO)
  this garden can be part of the community (ATO_C - yellow) or privately sold to one of the owners of the complex (ATO_P - blue)
• surface left as it is (OTO - not coloured)

The next thing I check is the gross floor area (BVO) with a distinction between inside (BVOi - green) and outside (BVOe - purple) according to the rules mentioned above.

Then we get to the inside: the net floor area (NVO). 
Since the defined functions are only related to the defined space nr 8 "space where people remain", I use the code 8.01 for living, 8.02 for meeting, etc. 
In the category 8.11 I make further distinctions:

• 8.11a garage
• 8.11b storage 
• 8.11c changing rooms
• 8.11z other functions

Each room/function has again its own distinct color to use on plans. In this way I develop a visual "feeling":

For developers it is important to make a distinction between floor levels under the ground and floor levels above it. However, the standards don't give any answers when the soil isn't horizontal. The European Commission uses for his own buildings following method:

Level 0.00 on the outside of the facade is the level of the foothpad in the middel of the facade.
The floors who are situated between this outside level 0.00 and 1,50m below it, are considered "above groundlevel".
The Uniformat Classification uses A to mark the substructure en B to mark the superstructure and shell. In the development code I "borrow" this A and B.

Another important issue for developpers is to know the ratio between spaces used for the community and spaces to be sold to several owners. The first space I mark with a "C" and the latter with a "P".


An exemple of the Development Code: ACi8.11a

• A : the space is to be found under groundlevel
  B is above groundlevel
   
• C: the space is used by the whole community of owners
  P is space exclusively for a private owner
   
• i: the space is completely surrounded by walls
  e is outer space adjacent to the facade
   
• 8: space used by people
  see above for the other defined spaces
   
• 11: other functions where people are not constantly present
  see above for the other defined functions
   
• a: garage

Kind regards,
Peggy

For beginners: how to determine a selling price ?

This is one for estimators at the beginning of their carreer and for those who are struggling with the calculations of their estimation software. Or, when you put it the other way around, how should your estimation software calculate ?

For the clients and architects who want to peep inside the kitchen of a general contractor: a warm welcome as well :o)

Here we go.

STEP 1

In a classic tender you have a list of articles where you have to put a price on.
Read carrefully the specifications and estimate the according costs for labor, material, equipment and subcontractors, article per article.
When finished the software will totalise this. These are the DIRECT COSTS.

STEP 2

As stated in my previous articles on this blog (and elsewhere), there are things you need in order to realise the building but which are not specifically mentioned in the tender.
Not estimating them will certainly result in a furious boss !
Some contractors estimate these costs in a seperate Excel file, some do this in the estimation software. It doesn't matter where you estimate it, as long as the job is done. 

The total sum of these costs are the INDIRECT COSTS.

Usually your boss wants to know how big these costs are related to the direct costs, preferably expressed in a percentage. How much this should be, really depends on what is specifically asked for in the tender: it can go from less than 1% when the architect wants to get a feeling with how a project is actually realised and mount up to 15% when it doesn't interest him at all.

STEP 1 and STEP 2 together is the PROJECT RELATED COST for the contractor.

In a formula:
                        project related cost = direct costs + indirect costs


STEP 3

A contractor has an office, an accountant and all other kinds of costs. 
And these costs remain whether he has a full order book or not. 
These are the GENERAL COSTS (in Dutch: algemene kosten or AK). Usually, these costs are taken into account bij adding a percentage on top of the production cost. 

In a formula:
                        total cost = project related cost x (1 + % general costs)

Some considerations:

• Each contractor has a slightly different view on what is project related and what not.
  E.g. some contractors have a standard all risk insurance which is part of the general cost percentage; others look at the insurance project by project and add its cost to the project related cost.
• Another thing: how big is the contractor you work for ? Does your company has his own engineering department ? In that case the general cost will be higher than the small contractor who only executes what is written down in the tender.

So, for you, as a beginning estimator, it is important to know what your boss exactly means by "general costs". Usually, the percentage is somewhere between 4% tot 8% of the project related cost.

STEP 1, 2 and 3 together is the TOTAL COST for the contractor.


STEP 4

A contractor wants / needs to make a profit. And your boss is not always so sure of the quality of your work. He will therefore add a percentage on the selling price for profit & risk. 

In a formula: 
                         selling price = total cost / (1 - percentage for profit & risk)

When you want to know how many euros or dollars this "dream" percentage for profit & risk is, the formula becomes:

                        profit & risk = selling price - total cost


STEP 5

Now we know what the total selling price will be, but how do we divide it over the articles of the tender ? Again, there are several considerations

• Sometimes, clients indicate a fixed sum for certain articles.
  E.g. kitchens in apartment blocks. The final, individual owner of the apartment gets a fixed sum to buy the kitchen of his dreams (what happens when he wants to buy a more expensive or less expensive kitchen, I'll tell you in one of my next contributions to this blog). In these cases you're selling price is known and needs to be fixed .
  In the direct cost of that particular article you put 80% to 90% of the fixed sum depending on the general cost percentage you agree on with your client ànd the discount you expect to get from the subcontractor who actually will build the kitchen.
  
  When you make your estimation in Excel, add a column where you can add e.g. an asterix (*) to mark these prices.
    
• Sometimes, the client already consulted subcontractors for e.g. windows.
  In other words, your client knows the price of the external joinery.
  
  Two remarks:
  
  1. When the client intends to work with a general contractor, he knows that the coördination of all the subcontractors come with a cost. In my experience clients are willing to pay from 3% up to 15% for it.
  
  2. As a general contractor you will get a better price of the subcontractor than your client because he is a one time client and you are a regular one.
  
  1. and 2. together means that you can put a selling price for these kind of items between 90% up to 110% of the direct cost of that particular article.
  
  Again, when you make your estimation in Excel, add e.g. an asterix (*) in the additional column to mark these prices.

Thus, the first thing you do after you have determined the total selling price, is to deal with the kind of articles mentioned above.

The total of these FIXED SELLING PRICES can be called SP1 (in Dutch VP1, verkoopprijs 1). 
The RELATED DIRECT COSTS need to be totalised as well and can be called DC1
(in Dutch KP1, kostprijs 1).

Secondly, you have to deal with the remaining articles.

The total sum of the REMAINING SELLING PRICES  can be called SP2. 
The total of the RELATED DIRECT COSTS can be called DC2.

The MULTIPLIER (in Dutch "overslag") of the direct costs in order to determine the individual selling prices of the remaining articles can be obtained by dividing the total of the remaining selling prices by the remaining direct costs.

In formulas: 
                         SP2 = selling price - SP1
                         DC2 = direct costs - DC1
                         multiplier = SP2 / DC2

As you can tell from above, the multiplier can have a wide range. When do you need to start worrying ? When the multiplier drops below 1,05 or exceeds 1,35. In those cases you better go and look for mistakes in your estimation :o)

Good news: for the time being, your job as an estimator is done.

STEP 6

It would be nice if the initial bid automatically results in a final contract. Perhaps this is the case in Utopia but certainly not in our daily construction world. Several times you will need to adjust you bid because of new quantities, new items, etc.

Before you make you're first adjustment, freeze all individual selling prices ! If you don't the formulas will start running their own life and you'll end up with different selling prices for articles where nothing changed. And trying to explain this to the client is an annoying thing to do and therefore is to be avoided at all times !
This also means that, in this phase of the selling process, you really need to keep your head cool.

There are several possibilities:

• Only the quantity changes.
  In this case, you only need to adjust the related the direct cost but be aware.
  E.g. a pump to pour concrete will have no different cost if you pour that day a couple of m³ more or less. In other words, the selling price remains the same but the percentage of profit & risk might drop or increase.
  You could keep the same multiplier but all this small changes in individual selling prices of the tender will unnecessary complicate the sales process.
   
• A new but similar article is added.
  In this case you need to apply the same multiplier as the one used with the existing simular articles. The selling price needs to be logical for the client !
   
• A really new article is added.
  Here you have a choice in which multiplier you will use: the same as in the first bid or a different one. To make the choice you have to consider whether this new article has an influence on the indirect costs. It is also an opportunity to correct the dropping percentage of profit & risk due to only changing quantities or to correct a mistake you find in your estimation after handing over the bid to the client

What is important for your boss ? That is simple: how much money is left for profit & risk when the contract is signed ! And he will certainly compare this to the initial "dream" percentage which was set out in the first edition. So it is really important to keep a record of the changes you made throughout the sale process.

Not all that simple, but it surely is the most fun part of estimating !

Kind regards and keep warm this weekend !

Peggy

Explaining BouwData - part 7

Before moving on, it is important to be sure that we all speak the same language. Especially for the interpretation of the NEN 2634 this is important. So here a little lexicon made by the university of Delft:

• COMPLEX (same word can be used as well in Dutch as in English)
  This is a collection of buildings who are somehow related to one another
    
• BOUWWERK or building in English
  This is the complete collection of functional and/or physical objects needed to give a solution to the need of housing (this can be a real house or a factory, hospital, school, etc. but not a road or bridge or solution for traffic)
  
  In the NEN 2634 the division of costs on this level is defined in table 6
  An exemple: 2 bouwkundige werken or, in English, constructional works
    
• ELEMENTENCLUSTER or a cluster of elements in English
  This is a group of elements with related characteristics
  
  In the NEN 2634 the division of costs on this level is defined in table 7
  An exemple: 2A fundering or, in English, foundation
    
• ELEMENT (same word can be used as well in Dutch as in English)
  This is a functional object with a specific purpose belonging to a building without being related to a specific physical solution.
  An element has a one-to-one relation to a building part
  
  In the NEN 2634 the division of costs on this level is defined in table 8An exemple: 2A.13 lagen op grond or, in English, layers on soil, explained as a layer designed to carry 3 t/m² and with a flatness of 5mm over a 2m length
    
• BOUWDEEL or building part in English
  This is a physical object with a specific performance just because of the materials used and the way it is constructed.
  A building part has a one-to-one relation to an element
  
  The layer on soil described as an element can also be described as a building part and it sounds like this: a layer on soil made out of 20cm concrete C25/30 with 25kg/m³ steel fibers on a PE foil of 0,2mm and layers of 5cm sand and 30cm of chippings
    
• COMPONENT (same word can be used as well in Dutch as in English)
  These are the physical objects with a specific performance where building parts are made of.
  
  The NEN 2634 stops at the level of element but when you look beyond the summary of table 1 of SfB you find everywhere on the internet, you see something usefull.
  Especially when you look into the BB/SfB-plus which prof. Frank De Troyer from the University of Leuven published in 2008.
  An exemple: 2A.13.0 - demolition, excavation for layers on soil
    
• ACTIVITEIT or activity in English
  This is a process of putting into work materials using labor and equipment
  
  Here, we enter back into the field of the material code and, as I wrote in one of my previous blogs, STABU is here much more usefull than the table 2 and 3 of SfB.
  One can say that the activities are the molecules of an estimation
    
• MIDDEL or means in English
  This is a general information carrier for building materials, labor or equipment
  One can say that the means are the atoms of an estimation

Sounds interesting, doesn't it ? Certainly when you put it into a nice PPT slide:

I thought so as well when I started to put it into daily practice. 
It didn't take long to figger out that this was all too theoretical.
Let me give you an exemple: 2D.31 exterior wall openings. 
The idea is to have cost knowledge on a very rudimentary level when designing: a cost per square meter opening. This implicates that, when you want to put detailed estimations into a database, that you put the costs for big megadoors, ordinary windows and doors and automatic entrance doors all together in a big blender to generate the cost indicator of the exterior wall openings for that particular project.
So, I did. 
But I ended up spending a lot of time writing down what the result really meant and when I needed to use the database I always felt very insecure.

On top of that, when I looked at table 6, I felt I didn't have the means to make proper distinctions between the different mass studies I had in front of me.

I had to figger out something else.
And the answer was quite easy: move everything one phase up !
So, my nice PPT slide now looks like this:

I'm using it now for a couple of years and it never has let me down !

Kind regards,
Peggy
www.bouwdata.net 

Explaining BouwData - part 6

First there was the sun with outdoor activities and then there were a lot of classic tenders to make a bid on. So, in the past month, my workplace resembled a lot my fancy old office filled with boxes full of paper. Luckily the paperwork was replaced by digital files. But there was another difference: although the projects where very different and for multiple clients, I always felt part of a team. So, to all of these clients: a warm thank you for achieving where my previous bosses failed !

But back to the future and BouwData now. 

The backbone of the different sets of agreements is the object code, a code with focus on function and life cycle cost. It can be used from the early consideration to invest in real estate to the phase of real cost engineering where knowledge about labor, material, equipment and subcontracting is necessary. It is from the object code that you can relate to the material code - the language of the contractor - and to the development code - the language of the developer.

It will take me some "parts" to explain its full depth, though.

The starting point was, as with the material code, the search for the standards to be used. And again the Netherlands proofed to be way ahead of Belgium.

On the highest, most general level, you have the same standard in Belgium and Holland: the NBN B06-003 / NEN 2631. This standard started his life in the Netherlands in 1979 and Belgium followed in 1983, 5 years later. Its focus is on investment costs and sums up, quite precisely, the kind of cost you need to consider :

1. the acquisition of the ground you want to build on and the costs you have to make it ready for the contractor to plug in the socket and start building. Yes, this includes getting rid of trees, bushes and all kind of dirt, making sure that the groundwater has dropped sufficiently  if necesarry and that electricity and water is available on site.
   Why ? Well, these costs can have an influence on you're choice of spot you want to realise your project on, more or less regardless of the design
2. the cost of the building itself including all equipment which is fixed to the building and not related to the production process which will occur when the building is in use.
   Important to notice: in this fairly old standard they already stated that there are different levels and ways to look at these costs: from the point of view from the developer (e.g. if you want to build a hospital, costs are in the earliest phase related to the number of beds), over the point of view from the designer (elements of the model), what you need when tendering to the point of view from the constructor (the sequence of coming to the building site).
3. the cost of equipment related to the use of the building
4. additional costs such as fees for designers, assurance, financing, moving into the building, etc.

Quite I good start and still accurate today but it is lacking detail.

In 2002, they realised this in the Netherlands as well. So they made the NEN 2634 which related the previous standard on investment costs to the international table 1 concerning elements of a new design of the SfB, the international classification system for construction. In this standard they define more precisely all phases of the design and building process and state how costs should be defined in every single one of them.

The object code is also the set of agreements to discuss Life Cycle Cost. 
The previous standards where made in a time where the world of design & construction had nothing to do with the world of facility management. In those days, nobody had ever heard of LCC. So I searched for standards in that world and yes, they also had felt the need of organising their costs. And again, the Netherlands proofed to be ahead of Belgium. They installed the NEN 2632 in 1980 and Belgium followed by taken it entirely over in 1983, calling it the NBN B06-004.

So, looking at all these standards I had sufficient background to relate it to my 15 years of estimating experience.

How ? Read the next part ! And I promise not to wait another month this time :o)

Kind regards.
Peggy
www.bouwdata.net 

Explaining BouwData - part 5

To realise a building you need money. Whether you are a developer, designer or constructor it is the same amount of money you're talking about. The way you look at this sum is, on the contrary, totally different. This I made clear in one of my previous blogs. Therefore, to gain knowledge I created three codes:

• the development code for developers with emphasis on floor surfaces
• the object code for designer with emphasis on functions
• the material code for constructors with emphasis on materials

Today, I'm going to give you some background on the material code.

To the developers and designers who are thinking: "this doesn't interest me at all !" and whose finger is now moving to the little cross in the right top corner of the screen, I would like to ask to hold on a second. Your attitude is typical 20th century. In the 21th century it is all about transparency and communication (*). And in order to communicate properly, you have to know how the other person thinks and what his needs are. So, please, take a good glas of wine and continue reading. You won't regret it :o)

Having this off my chest, let's go back to the material code. This code is all about how and with what kind of material you are going to realise the building. To know what's available on the market, Google is an excellent tool. But for some products you have standard contracts and certain knowhow is the same in every project. This knowhow is sometimes even exclusive for your own company. So, beside a good search engine on the internet,  you also need a little database of your own to store adresses of favourite suppliers and subcontractors, to keep interesting offers which might be interesting for other assignments in the future and to write down the personal knowledge you gain while working your way through several projects. At least, I felt this need and I see that fellow estimators are struggling with the same issues. A lot of them invent their own structure for this database. I prefer to work according to existing standards. And for this problem there are two possibilities: table 2 and 3 of SfB or the STABU from Holland.

At first I tried to work according to the SfB because this is a worldwide spread classification method for construction. This meant analysing every single thing you purchased by material and by form. For concrete this is simple enough: it will be poured on site so according to table 2 we have code E. And it is made out of sand and stones bind together through a chemical process using water and cement. According to table 3 we have code f2. Together you write it down as Ef2. The code of an Argex block is Ff5. But what with a toilet ? In an estimation this is usually offered by a subcontractor for one single price. No problem: in table 2 I had X for complex shapes and in table 3 I had a if I didn't want to specify anything or if I simple didn't know whether the material was made of organic or anorgonic stuff.

Mission accomplished ?

Since I am quite a perfectionist I spend a lot of time to make sure that the Xa category was kept to a minimum and explaining to people why they should use f2 and not f5. 

Now I had a fairly large Excel file and could start sorting. Problem: in alphabetical order I got a list which hadn't anything to do with the order of materials coming on site. And searching on codes was really hard since there wasn't any connection with the word (nor in Dutch, nor in English) so memorising was a nightmare.

Mission failed, yes ! 

And now I also knew why people in Holland so firmly sticked to their STABU :o)

So, I tried it that way but added something to make it even better: I used the coding of STABU chapters and STABU paragraphs and added a 2 to 4 lettercombination. Poured concrete became 21.50.BET (concrete is beton in Dutch), classical wooden formwork became 21.32.HOUT (wood is hout in Dutch), etc. All items concerning pouring concrete on site were gathered in the 21 chapter, all masonry in chapter 22; just as the order you encounter these items while realising the building.

The 2 to 4 letterword had several advantages: it helped to memorise the codes and it allowed me to make distinctions or add items as much as I wanted to. E.g. next to classical wooden formwork, you also have things like Framax, a system of panels to construct the formwork or additional layers to add texture to the concrete surface. These are all different suppliers but are all to be estimated in the paragraph 21.32 contemporary formwork. In the material code I have now:

• 21.32.HOUT bekistingshout
• 21.32.MAT structuurmatten
• 21.32.SYS systeembekisting

And if a contractor wants another category, well, he simply has to search the according STABU chapter and paragraph and add a two to for lettercode to make the distinction with the other categories in the paragraph.

Another exemple: suppose you have a young trainee estimator in your company who needs to estimate pile foundations inside a building which needs to be renovated - or you as designer or developer start getting an interest in technical solutions ;o)

Instead of starting a search on Google, he or she could start her search in the companies database by using the material code 20.32.REN as a key: 

• in the database with adresses he can find the subcontractors the company already worked with
• in the database with company related experience she knows the additional things to pay attention to
• in the database with ancient offers, he can see the level of cost to expect

So before bumping into your office, the trainee already knows the basics and the time spent together can be used to focus on the SWOT of the project itself. Quite efficient !

But on top of that, the material code in combination with the cost type and the number of the supplier or the number of your library also form the "atoms" of an estimation. 

• 21.50.BET.10.000 - labour pouring concrete
• 21.50.BET.20.25/30EE2/EA1S320 - concrete C25/30-GB-EE2/EA1-S3-20mm (**)
• 21.50.BET.30.32 - concrete pump with a reach of 32m
• 21.50.BET.40.XXX - subcontractor who makes component XXX with his own material and equipment

I am now using this code for six years and never find myself in any trouble. A new material gets his own material code and the possibilities of creating "atoms" for my estimation are endless.

So I, like the people from Holland, am 100% pro STABU :o)

The material code in pdf format can be found on www.bouwdata.net under "downloads".

If you want to receive the material code in Excel format, just send me a mail pbo@pbcalcenconsult.be.

Unfortunately the material code only exists in Dutch. So, if anyone who speaks English from when he or she was a todler and learned "construction" Dutch during his professional carrier, please contact me as well ! Because I would love to make an English version of it.

Kind regards and enjoy the sun !

Peggy

www.bouwdata.net or the Linkedin Group "The Art of Estimating"

(*) look around you and read Alvin Toflers "Third Wave" and after that "The New Normal" by Peter Hinssen and you'll know what I am talking about ;o)

(**) another possibility is to use a simpler number after the cost type. We used to do this because in some estimation software you needed to type the entire code manually.  The disadvantage was that if there comes another type of concrete on the market who is something between two existing types, it ends up at the end of the line with the next number. In modern estimation software you "click" or "drag" the code. So it is better to use a longer code which leaves room for new products to find their place between existing ones.

Explaining BouwData - part 4

When I left my fancy office in 2006, I didn't stop estimating. Quite on the contrary. Where estimating was previously merely a necessity to get the contract signed, it is now the end product of my business. And because of this shift in focus, I realised how sloppy me and fellow estimators sometimes worked.

Let me give you an exemple.

Masons are hard to find. And good masons often start their own specialised company. Therefore, general contractors often depend on them to get the job done. So, when estimating a project, you ask their price. Way too often this price is put into the estimation as a subcontractor. But most of the time these people only bring their own trowel. Bricks and mortar are to be bought by the general contractor; vertical and horizontal transport is to be done for them with the centrally placed tower crane.

Important question: how do you know whether this one tower crane is sufficient to get the job done in the most efficient way ? Well, out of the estimation you derive all the labor hours. Devide them by 8 hours per day and you get the number of "labor days". You  think you will hire the tower crane during e.g. 10 months. In one month you have, on average, 17 to 18 days that people work on the site. Multiply the 10 months by 17 or 18 and you have the "crane days". Divide now the "labor days" by the "crane days". When the result is 8 to 10 this means that, on average, 8 to 10 people are working on site at the same time. In this case you will be doing just fine with this one tower crane. With a higher result the men will have to wait to get their material to work with. With a lower result, the tower crane is not used at its full capacity.

Now, suppose we put the masons we hire as a subcontractor in the estimation. When deriving the labor hours, their hours will not be taken into account. But these people expect that you get the material to the spot where they work in time. If not, they will not be able to work at the estimated efficiency and they will lose money. And people who lose money while working, are usually not the people who deliver the best job. So, in the end the general contractor himself is the victim.

Another issue: all kinds of labor are put in the estimation by the same code because it is usually the same price. Suppose that, at the moment of estimation, it looks like it that there will be enough masons in your own company available for the job. When deriving the labor hours from the estimation, the check of the centrally placed tower crane will be done correctly. But suppose that there is a delay and when the project eventually starts, there are no masons available anymore. Now you have to go through the whole estimation and add up manually how many hours were ment for masonry in order to create a separate budget for these hired masons. In our digital age, a real stupid thing to do.

What can we do about it ?

Apply the set of agreements of BouwData on cost types :o) 

Which cost types do we have ?

• the classic MAMO, used when the design is finished and when the budget is made to do the purchases. But there are costs which can't be considered as a MAMO e.g. costs for assurances, taxes, etc. In BouwData the code 00 is used to summarise all general funds in the estimation
  
  - A of "arbeid" which is Dutch for all kinds of labor: the wages of the workers on site as well as the wage of the projectmanager, as well for own staff as for hired people.
  Further distinction is to be made by the material code (will be threated in part 5 of this blog). In BouwData the code 10 is used to summarise all labor in the estimation
  
  - M of "materiaal" which is Dutch for deliveries, costs for materials used in the building or which can't be used afterwards (e.g. the notice board with all the building partners). In BouwData the code 20 is used to summarise all deliveries in the estimation
  
  - M of "materieel" which is Dutch for equipment, costs for all the things which don't remain on site and can be used in a following project. In BouwData the code 30 is used to summarise all equipment in the estimation
  
  - O of "onderaannemer" which is Dutch for subcontractor: people who come on site with their own materials and/or equipment to realise a component of the building.  In BouwData the code 40 is used to summarise all subcontracts in the estimation
  
  
• As I stated in my previous blogs, there are also other costs to be considered while estimating:
  
  - AK of "Algemene Kosten" which is Dutch for general costs not related to any particular project. Usually this is a percentage added to the cost types mentioned above between 5% and 10%
  
  - W of "Winst" which is Dutch for profit: the estimated selling price minus the estimated costs. Usually this is also a percentage added to the cost types mentioned above.
  
  - R of "Risico" which is Dutch for risk: this is an amount of money for unexspected events.  Usually this is considered together with the profit and can go from 0% up to 10%.
  
  - S of "Stelpost" which is Dutch for a fixed sum. This is used when there are no details available for a component which certainly will needed to be build. E.g. a kitchen in an apartment block.
  
  
• But before purchasing, while designing there is also a need for estimations. In this phase it is too soon to go to the market to ask for prices, though. Usually you search in a database with cost ratio's. There are three levels of cost ratio's, all related to the object code and phasing of projects (will be threated in one of my next blogs as well).
  
  - cost ratio related to the "elementcluster", which is used when defining the programm requirements
  
  - cost ratio related to the "element", which is used when making the structural design
  
  - cost ratio related to the "component", which is used when finetuning the design

All eight sets of agreements are related to each other. Don't expect to understand and see all relationships at the first glance. But believe me, once you get the hang of it, it is a very usefull tool to keep your budget under control. And if you have any questions, just ask !

Kind regards,

Peggy

www.bouwdata.net

Praktische richtlijn: gunningscriteria bij offerteaanvraag

Beschouwingen zijn leuk, maar praktische richtlijnen zijn handiger. En ik had beloofd om ook deze laatste via mijn blog mee te geven. Bij deze :o)

Via volgende link vind je gunningscriteria voor een algemene offerteaanvraag.
http://www.pbcalcenconsult.be/gunningcriteria%20bij%20algemene%20offerteaanvragen%20NL.pdf 

Prettig weekend.

Vriendelijke groeten,
Peggy
www.bouwdata.net 

Explaining BouwData - part 3

Another lazy saturday morning after a great evening at Jazz Middelheim. Blog time.

For the last time in these series, let's go back to my fancy office filled with boxes full of paperwork . One of all the documents is the bill of quantities. As an estimator you are expected to put a price after each item mentioned. Quite obvious. 

Unfortunately most of the time the items mentioned only concern products which make up the building itself. Construction involves a lot more than the concrete, bricks and mortar though. Questions like which crane will we use, how many hours do we need for figuring out every detail, is there water and power on site, who are we putting on site to organise everything, etc. ... they all come with a price. And beside these additional costs related to the project, there are also general costs like housing, accountancy, a staff party every now and then, etc. ... to be considered. And there is the issue of profit. Or adding an additional percentage for the risk if you are running out of time and can't check everything to the detail you want to. It's quite some work.

"And a lot of words but give me some figures", I hear you think. Well, the costs of the site installation, the organisation, the general costs and percentage of profit and risk all together mount up between 20% for a big apartment building to 35% for a complicated renovation project related to the sheer production cost.

So when there are no specific items for it in the bill of quantities, you need to add these costs in another way. And here comes the catch. Or better, the commercial thinking pops in. 
Let me give you an example. Suppose you heared that the project developer is considering to take the windows out of the tender and intends to order it directly to the subcontractor. In this case you will add no additional fee to the items suspected to be cut out of the tender. You might be satisfied with less turnover but not with less profit or less money to cover your general costs. And now suppose that your collegue-competitor-contractor doesn't have this information. He will normally split the additional costs equally on all the items mentioned in the bill of quantities.
The result is that you will end up with pricelists very difficult to compare all depending on the commercial view of the contractor on the project.

So here is what I suggest:

• Don't judge by price only. Look at his willingness to share technical support, check the references.
• Treat installation site and organisation on site in the same way as production costs. And do make a difference between fixed costs and costs related to the execution time
• Negociate on the percentage of general costs, profit and risk. General costs between 5% and 10% are normal depending on how many support the contractor can offer (e.g. when he has a whole team available to study stability issues, making BIM models etc it is obvious that he has higher general costs than the contractor who only know how to pour concrete). Percentage for profit and risk go from 0% up to 10%. I usually aim, when working with open books and a real building team for 7% general costs and 3% profit & risk. On top of that I make the deal that further profit gained while actually purchasing is cut in two: 50% for the contractor, 50% for the owner
• When you work with a real building team and open book system, make sure you have a coach and concentrate all administration to one hand. Use groupware and let everyone focus on what he or she is best at. Don't forget that the design team and contractor team are used to be on different sides of the curtain for decades. In a building team it's essential that they are at the same side !

So now you know the history of estimating and got a glimps of the future. 
Next time we'll start discussing the 8 sets of agreements in detail. 

Kind regards,

Peggy

www.bouwdata.net 

.

Explaining BouwData - part 2

What did I learn in that fancy office of mine ? Well, only knowledge on a very detailed level.

Why ? The content of every box was different. Of course, I hear you thinking: it's another building ! But it would have made my life easier if every architect delivered a bill of quantities with a simular structure. Like they do in Holland. There, if you see the number 22 every estimator of every contractor knows it's about masonry. I, on the other hand, always felt like a detective the first days when the box arrived: was the doorframe to be included in the price of the door ? If not, where could I find it in the quantity take off ? And needed it to be painted ? If yes, where did I have to put that price ? Together with the doorframe or was there a separate item for it ?

Imagine our accountants all working according to their own set of rules. And imagine you switching to another accounting firm. All the figures which ment something for your previous accountant would be worthless for the new one because he uses a different system of analysing your books. And what about the government ? Annual balance sheets of every accounting firm would look different ! Impossible, you think. Well, that's exactly how our Belgian construction industry works : every architect has his own way of making a quantity take off.

Are they to blame for not organising themselves better ? I don't know. There are some documents available but they all have a narrow point of view. E.g. the VMSW has it's focus on social housing. Therefore it is not suited for e.g. a factory building. And the coding system they use is not related to any Standard. 

Which brings me to the real bottle neck. Why ? 
Let me start by explaining the different viewpoints you can have on a building.

First there is the developer. This guy - or lady - is interested in selling the property. So, if the prices of car boxes in a basement don't exceed the cost of the basement, he won't bother to build it. What else does he wants to know ? How many gross floor surface he has to built and how many square meters of it mean a profit when selling.

Then we have the designer. He - or she - wants to create something for mankind, something to be remembered by. But often the design of his dreams costs too much. So the designer has to skip things. What if he removed that window out of the model ? Costwise this means that not only the window has to disappear but also the beam above, the plasterwork on the sides, the sill on the outside, the tablet on the inside, the occasional ornament around the window in the facade,...

And the constructor ? He doesn’t care about the things above. He needs to do some purchases: concrete, reïnforcement, coffrage, bricks, mortar, … and he needs to make an evaluation whether he is going to work with his own laborars or with subcontractors. Very different than making an investment plan or modelling the best design !

So, if you let all of this people make a list of articles to tender, it will have a very different structure, depending on the knowledge it needs to generate.

For decades we held on to the single tree structure assuming that the headlines will give the investor the knowledge he wants, assuming that the subtitles will generate the costs the designer needs for swift changes and assuming that the detailed description will deliver a full shopping list for the contractor.

This is simply not true ! 

So, in 2008 I got some money from IWT to create an accounting system for the construction industry. Since then BouwData evolved from just a coding system to a working method based on existing Belgian and Dutch Standards, to control costs, quality and communication in all phases of a building: from early consideration to invest over design and construction to use and demolition. And I do this by 8 sets of agreements which I am going to explain one by one in my next blogs. So keep following me :o)

Kind regards,

Peggy

www.bouwdata.net 

Explaining BouwData - part 1

A lot of people ask me what BouwData exactly is.

I usually refer to the homepage of www.bouwdata.net where you can find powerpoint presentations in Dutch: a rather small one (33 slides) and the big one I use when I give lectures (126 slides).

The next reaction I get is "BouwData is really complicated". Well, it is ... 
and it isn't at the same time. In the whole building process, there are just a lot of things to consider if you want to get beyond the administration and generate knowledge through your estimation.

Yesterday someone said my previous blog was too long. But that, although he doesn't know anything about construction, he could understand what I was talking about. A nice compliment and usefull remark. Thanks Geert !

So, I am going to keep the examples but cut things into little pieces. And I am going to start at the very beginning: my frustration working as an estimator at fairly large construction companies. And no, it hadn't anything to do with annoying bosses ! It's all about how the system has grown over the past decades.

How did it work back then (*) ?

First, you got a fairly large office space where people delivered boxes filled with paper. I am speaking now about the non-digital age - seems way back but it is actually less than a decade ago that everything was put on real paper. Anyway, the paperwork in front of me was the result of months, sometimes years of work done by a design team. And I got usually a couple of weeks to find out what they exactly wanted and how much it would cost for our contractor team to turn this paperwork into reality over the months, mostly years to come. 
So the pressure was on ! 
It was balancing on the edge; always going as cheap as possible gratefully using the mistakes and voids in the paperwork. Always hoping you would end up first by less than 2% under the second price. Finishing first with a bigger difference and you could start sweating: where is the mistake ? And ending somewhere else in the ranking always sucked, no matter where you stranded. All your work of the past weeks went straight down the drain. But there was no time for grieving or extensive joy because there was the next box to be analysed.

And the boxes kept coming and the prices for buildings kept finding their way out of the door. But never were you really part of a team: you analysed what the design team had done and you tried to predict what the contractor team would do. Yes, I had a nice office but it was lonely in there. And over the years, the quality of the paperwork dropped, the time for analysing got shorter and the assistants you had for administration disappeared because of severe remediation .

"Design-bid-build" really cuts the building process in two. And the way the bid is done puts the two teams at state of war. Sometimes it gets even vicious. To get that assignment the contractor works hard: one out of ten offers made ends in a real contract. Indeed, I wasn't the only one to receive that box and to work for several weeks in a fancy office ! At least 7 other collegues got that same box and where expected to make a bid. With 8 competitors the design team would surely get the lowest price ! 
And when times are tough, the prices drop even more. So if you see mistakes or voids, you keep your mouth shut and work on solutions behind the scene. Once the contract signed, you put your cards on the table. And the changes required to realise the building don't come cheap. But in order to survive, the contractor has no choice but to play the game by these rules. And the victim is the owner: he sees his lowest bid increased by 20, 30, ... %

And all the time I  felt stuck in the middle. Why wasn't it possible for both teams to work together on the design ? I could join this mixed team and do the quantity take-off and estimation as an independent consultant ... that's my dream and that is what BouwData is created for !

How ? See next time in part 2 :o)

Kind regards,
Peggy
www.bouwdata.net

(*) actually, in a design-bid-build process it still works like this.

Life Cycle Cost: what does it really mean ?

Until recently BIM, Building Information Modelling, was the talk of the town. Nowadays everyone seems to be talking about Life Cycle Cost. To estimate this you first of all need to know something about Net Present Value. In the article you can find on http://www.pbcalcenconsult.be/Life%20Cycle%20Cost%20EN.pdf I tried to shed some light on these related subjects and tried to find out what it could mean in daily practice.

Tot voor kort was BIM, Building Information Modelling, het modewoord bij uitstek. Vandaag is dit verschoven naar LCC, Life Cycle Cost. En als je LCC zegt, dan dien je meteen ook NPV, Net Present Value, in ogenschouw te nemen. Waar de meesten in de Belgische bouwwereld zich nog iets kunnen voorstellen bij LCC - wat nog niet betekent dat ze het ook effectief kunnen berekenen - , wordt het heel donker als NPV ter sprake komt. Maar troost je, ook ik hoorde het in Keulen donderen toen een klant voor de eerste maal een studie over LCC met NPV aanvroeg. Het Engelstalig artikel waarnaar ik hierboven verwijs, is het relaas van de leerschool in deze opdracht. Meestal maak ik van gepubliceerde artikels ook een Nederlandstalige versie maar in dit geval was hett er nog niet van gekomen. Deze gloednieuwe blog en een luie zaterdagmorgen zijn de ideale omstandigheden om dit recht te zetten :o) 

Definitie

Laat ons beginnen met de definitie (*): "Life Cycle Costing is a technique used to estimate the total costs of a project, installation or facility during the whole of its economic life, taking into account all costs and benefits.” Iets wat we best kunnen gebruiken gezien er toch een heel pak nieuwe technieken op de markt komen die ons allemaal groot profijt beloven. En uiteraard allemaal duurzaam zijn. 

Bij LCC is de doelstelling de laagste LCC tussen de verschillende mogelijkheden te zoeken en niet om effectief de volledige kost an sich te bepalen. Daarom zal men in de berekening alle zaken die gelijk blijven, buiten beschouwing laten om zo de analyse te vereenvoudigen.

En om dit allemaal een beetje inzichtelijk te maken, is het nodig om dit te doen binnen de krijtlijnen die door diverse normen zijn uitgetekend.

Met een voorbeeld ga ik proberen om de diverse aspecten van LCC toe te lichten en doe ik een poging om enige regels voor LCC in België en Nederland te formuleren.

De beschikbare normen

In 2008 ontving ik subsidies van het IWT om een "rekeningstelsel" voor de bouwsector te creëren. Bij dit onderzoek heb ik de bestaande Belgische en Nederlandse normen geanalyseerd en op elkaar afgestemd. Het resultaat zijn acht afsprakenstelsels. Eentje daarvan is de Object Code voor LCC. Deze codering "lijmt" volgende bestaande normen aan elkaar:

• NBN B06-003 m.b.t. investeringskosten (identiek aan de NEN 2630)
• NEN 2634 en tabel 1 van de BB-SfB Plus m.b.t. kostenbeheersing tijdens het ontwerpproces
• NBN B06-004 m.b.t. uitbatingskosten (identiek aan de NEN 2632)

Je kan het beste iets uitleggen aan de hand van een voorbeeld - ik ben een grote fan van filosofische beschouwingen maar op een bepaald moment wil ik er effectief ook wel mee aan de slag, dus moet het hands-on zijn :o) - En we houden het simpel: de productie van warm sanitair water. De gerelateerde object code hiervoor is:

• kosten voor de investeerder:
  3A.53.3 initiële installatiekost
• kosten voor de facility manager:
  9B.3.3A.53.3 kosten energieverbruik in "slaap" toestand
  9B.4A.3A.53.3 kosten m.b.t. preventief onderhoud
  9B.4B.3A.53.3 kosten m.b.t. curatief onderhoud
  9B.4C.3A.53.3 kosten m.b.t. vernieuwen van de installatie
  9B.4D.3A.53.3 kosten m.b.t. herstelling na schade door de gebruiker
• kosten voor de gebruiker:
  9C.3.3A.53.3  kosten energieverbruik in "gebruiks" toestand

Kosten voor de investeerder

De investeerder is hier de eigenaar van een twee kamer appartement in Brussel en hij koopt een boiler met spiraal om het water opnieuw op te warmen (productie van warm water in combinatie met centrale verwarming) en een inhoud van 120 liter.

De inschatting van de investeringskost gebeurt als volgt:

• productie kost voor de aannemer:
  - aankoop van de boiler: € 422,50 (**)
  - aankoop van bijkomend materiaal nodig voor de installatie: € 75,00
  - arbeidskost: 3 uren aan € 42,00 per uur
• algemene, niet project gerelateerde kosten, winst en risico voor de aannemer (AK+W/R): 15% op de productiekost - hij komt immers achter andere aannemers en in de praktijk betekent dit constant herplannen - met de gebruikelijke 10% voor de ruwbouwaannemer komt hij er dus niet - tenzij we het bouwproces beter gestroomlijnd krijgen natuurlijk :o)

In totaal bedraagt de investeringskost dus € 717,03

Heel belangrijk in de vergelijking is de juiste context te kennen - en daar durft het schoentje nogal eens te knellen !

Eerst en vooral: werk je met een algemene aannemer en meerdere onderaannemers of werk je met onafhankelijke nevenaannemers zonder onderaanneming ? In ons voorbeeld gaan we er van uit dat de eigenaar een handige harry is die zelf de coördinatie op de werf verzorgt. De kosten voor deze coördinatie zijn te behandelen in deel 6 van de NEN 2634. Gezien de eigenaar in kwestie niet van plan is zichzelf een loon uit te keren noch het inschakelen van een algemene aannemer overweegt, kunnen we de berekening van dit aspect buiten beschouwing laten. Bij grote projecten wordt de overweging wel gemaakt en moet dit hoofdstuk dus wel degelijk mee opgenomen worden in de vergelijking !

Ten tweede: wie doet er de studie van de installatie ? De betrokken aannemer zelf of een apart studiebureau ? In elk geval, de kosten hiervoor zijn te behandelen in deel 8 van de NBN B06-003 en mogen dus niet op één hoop gegooid worden met de investeringskost. Gezien het hier over een heel eenvoudig ding gaat, kunnen we ook dit aspect buiten beschouwing laten. Maar opnieuw: bij grote projecten waar dit wel een issue is, moet het dus ook opgenomen worden in de vergelijking !

Kosten voor de facility manager

Het maakt weinig uit of de facility manager een aparte organisatie is of de eigenaar zelf. Technische installaties moeten deftig onderhouden worden als je er ten allen tijde geniet van wil hebben.

Marketeers hebben er baat bij deze kosten te minimaliseren. Het gebeurt maar al te vaak dat enkel de grotere investeringskost afgewogen wordt tegen het profijt dat gedaan wordt door het lagere energieverbruik. Een goede raad: tracht een realistische kijk te krijgen op de kosten voor onderhoud !

In ons voorbeeld hebben we te maken met volgende kosten:

• 9B.3.3A.53.3  kosten energieverbruik in "slaap" toestand
  € 0,00 gezien de boiler geen energie verbruikt als hij niet werkt
• 9B.4A.3A.53.3 kosten m.b.t. preventief onderhoud
  alle vijf jaar kan je best de kalk laten verwijderen en moeten de anodes nagekeken worden. Dit betekent dat de aannemer terug moet langskomen. Zijn kosten voor dit werk, indien het vandaag zou moeten gebeuren, zijn:
  - € 25,00 voor benodigd materiaal
  - 3 uren werk aan € 42,00 per uur (inclusief verplaatsing)
  - 15% AK+W/R
  of € 173,65 
• 9B.4B.3A.53.3 kosten m.b.t. curatief onderhoud
  € 0,00 gezien alle onderdelen dezelfde levensduur hebben als de boiler zelf
• 9B.4C.3A.53.3 kosten m.b.t. vernieuwen van de installatie
  we mogen er van uitgaan dat onze boiler 15 jaar mee gaat gaan
• 9B.4D.3A.53.3 kosten m.b.t. herstelling na schade door de gebruiker
  in een appartement staat een boiler gewoonlijk in een hoek of gesloten ruimte. De kans dat de gebruiker schade aanbrengt, is in ons geval dus verwaarloosbaar.
  Let wel op: wil je bij DBFM projecten discussies vermijden, dan is het van groot belang dat je omschrijft welke schade door de gebruiker gedekt is en welke niet. Ik denk bv. aan een DBFM voor een school waarbij de leerling in een colère aanval de spiegel boven de lavabo aan diggelen slaat.

Hoe lang duurt "life" in LCC ?

In een LCC berekening worden de kosten bekeken over een bepaalde periode, bv. over 30 jaar. Maar er zijn verschillende manieren om dit te doen. In overleg met mijn klanten, kwam ik tot volgende regels:

• Het jaar van de investering is jaar 0; jaar 1 is het eerste jaar van gebruik.
  In ons voorbeeld moet het eerste vijfjaarlijks onderhoud van de boiler gehouden worden in het begin van jaar 6, na 5 jaar gebruik
• We verwachten dat de boiler 15 jaar gebruikt kan worden. De kosten voor vervanging zijn dus te plaatsen in het begin van jaar 16. De volgende vervanging is gepland in begin van jaar 31. Maar of je dit dan effectief wel of niet doet, is een beslissing die je neemt in de volgende LCC periode van 30 jaar. Bijgevolg wordt de tweede vervanging niet behandeld in deze LCC periode.

Bij DBFM projecten moet je duidelijk stellen wat je precies na de LCC periode verwacht. Immers, als je bovenvermelde regels volgt, eindig je na 30 jaar met een boiler aan het einde van zijn levensverwachting. Aannemers en faciliteers hebben in een DBFM contract de verantwoordelijkheid gedurende een bepaalde periode en zullen op zoek gaan naar installaties die precies diezelfde levensduur hebben of een levensduur hebben die er een deler van is. Immers, jij bent op zoek naar de meest voordelige prijs en die gaan zij jou bieden.
Wil je op het einde van de contractduur een zo goed als nieuw gebouw, dan moet je dit heel duidelijk melden. Maar hou er ook rekening mee dat dit de vergelijking veel gecompliceerder maakt omdat je in dit geval ook zaken als kapitaalverlies en afschrijving in rekening moet brengen. Het is mijn mening dat dit de hele zaak onnodig bemoeilijkt. Vandaar mijn pleidooi voor bovenvermelde regels.

Als er mensen zijn die een concreet voorbeeld hebben van een LCC berekening die kapitaalverlies en afschrijving in rekening brengt, laat het zeker weten via een reactie hier of op de linked group "The Art of Estimating" of via mail naar pbo@pbcalcenconsult.be

Net Present Value (NPV)

In de afgelopen decennia had je de wereld van projectontwikkelaars enerzijds en de wereld van facility managers en gebruikers anderzijds. Bijgevolg hebben calculatoren - of cost engineers zoals ik het toch liever hoor :o) - bij aannemers steeds gewerkt met prijzen die op dat ogenblik op de markt van kracht waren. Wanneer we een LCC willen berekenen, moeten we evenwel anders te werk gaan.

Daartoe moeten we naar de basis principes van de financiële wereld. 

In algemene termen kan je cashflow definiëren als geld dat je op een bankrekening zet of er net afhaalt.

Veronderstel dat we € 100 op onze bankrekening hebben. Bij een jaarlijkse rent van 10% kunnen we na een jaar € 110 euro van onze rekening afhalen. Laten we het geld nog een jaar staan, dan kunnen we na 2 jaar € 100 x (1 + 0,1) x (1 + 0,1) = € 121 van onze rekening afhalen.

In dit voorbeeld staat de € 121 voor de future value. En die kan berekend worden met de algemene formule C x (1 + r) tot de macht t waarbij 

• C = cash op de bank vandaag (in casu € 100)
• r = rente decimaal uitgedrukt (in casu 0,1)
• t = periode tussen de cashflows (in casu 2)

Bekijken we het van een andere kant: stel dat we binnen 2 jaar € 121 nodig gaan hebben. Dan moeten we vandaag niet dat totale bedrag al aan de kant zetten want er is een bank die ons interest betaalt. Is dit 10% dan volstaat het dat we vandaag € 100 vast op die bankrekening zetten.

In dit voorbeeld staat de € 100 voor de present value. En die kan berekend worden met de algemene formule C / (1 + r) tot de macht t waarbij 

• C = cash die we van de bank na periode t van de bank gaan halen (in casu € 121)
• r = rente decimaal uitgedrukt (in casu 0,1)
• t = periode tussen de cashflows (in casu 2)

Normaal gezien wordt het leven alsmaar duurder naarmate tijd verstrijkt. Iets dat vandaag € 114 kost zal binnen twee jaar meer kosten t.g.v. inflatie. Laat ons veronderstellen dat deze 3% bedraagt. Binnen twee jaar zal ik dus voor datzelfde product € 114 x (1 + 0,03) x (1 + 0,03) = € 121 moeten betalen.

In dit voorbeeld staat de € 121 voor de indexed value. En die kan berekend worden met de algemene formule C x (1 + s) tot de macht t waarbij 

• C = de prijs die we vandaag betalen (in casu € 114)
• s = de jaarlijkse inflatie decimaal uitgedrukt (in casu 0,03)
• t = periode tussen de cashflows (in casu 2)

De rente op jouw bankrekening zijn een combinatie van twee zaken: uitgestelde consumptie en inflatie (of kapitaalverlies). Als je beide zaken in acht neemt, spreekt men van nominale rente.

Net Present Value is eigenlijk niets anders dan de som van de present values van alle cashflows naar en weg van je bankrekening over een bepaalde periode.

Terug naar onze boiler

Vandaag, in jaar 0, bedraagt de kost voor preventief onderhoud € 173,65.

Laat ons een jaarlijkse inflatie van 2% veronderstellen. Dan zal de indexed value aan het begin van jaar 6 € 173,65 x (1 + 0,02) tot de macht 6 zijn of € 195,56.
M.a.w. binnen 6 jaar hebben we € 195,56 nodig. 
Hoe veel moeten we dan vandaag op onze bankrekening vast zetten ?

Laat ons een jaarlijkse reële rente van 5% veronderstellen. 
De nominale rente wordt in dit geval 5% - 2% = 3%.
De present value is dan € 195,56 / (1 + 0,03) tot de macht 6 of € 163,78.

Bij het begin van jaar 11 hebben we een tweede preventieve onderhoudsbeurt.
Bij het begin van jaar 16 kopen we een nieuwe boiler maar bij het begin van de jaren 21 en 26 hebben we opnieuw preventief onderhoud te betalen.

En telkens passen we dezelfde formules toe.

Om de kost voor het preventief onderhoud over een LCC periode van 30 jaar te kunnen betalen, hebben we vandaag dus: € 163,78 + € 155,98 + € 141,48 + € 134,74 of € 595,98 nodig.

Om de kost voor de vernieuwing aan het begin van jaar 16 te kunnen betalen, hebben we vandaag € 717,03 x (1 + 0,02) tot de macht 16 / (1 + 0,03) tot de macht 16 of € 613,40 nodig.

Doen we dezelfde oefening met een jaarlijkse reële rente van 10% en dus een nominale rente van 8% ipv 3%, dan krijgen we volgende NPV:
- preventief onderhoud: € 307,41 of 48% minder
- vernieuwing: € 287,31 of 53% minder

Omgekeerd, veronderstel dat de inflatie 5% bedraagt zodat de nominale rente naar 0% zakt, dan krijgen we volgende NPV:
- preventief onderhoud: € 1630,93 of 174% meer
- vernieuwing: € 1565,18 of 155% meer

Zoals je kan zien, kan je met enig gegoochel in reële rente en inflatie zo wat alles bewijzen ! Doorgaans worden volgende waarden gehanteerd bij een LCC berekening:

• 5% reële rente
• 2% inflatie

Kosten voor de gebruiker

Bij een LCC periode van 30 jaar, 5% reële rente en 2% inflatie, hebben we voor onze 120 liter boiler met spiraal al volgende kosten bepaald:

• 3A.53.3 initiële installatiekost - € 717,03
• 9B.3.3A.53.3 kosten energieverbruik in "slaap" toestand - € 0,00
• 9B.4A.3A.53.3 kosten m.b.t. preventief onderhoud - € 595,98
• 9B.4B.3A.53.3 kosten m.b.t. curatief onderhoud - € 0,00
• 9B.4C.3A.53.3 kosten m.b.t. vernieuwen van de installatie - € 613,40
• 9B.4D.3A.53.3 kosten m.b.t. herstelling na schade door de gebruiker - € 0,00
• 9C.3.3A.53.3  kosten energieverbruik in "gebruiks" toestand - ???

Uit bovenstaand overzicht blijkt dat we enkel nog maar de kosten m.b.t. de energieconsumptie in "gebruiks" toestand moeten bepalen.

Het vastleggen van de energieprijs en de bijhorende inflatie is het meest netelige item van de hele LCC berekening. Bij mijn opdrachten gebruik ik de cijfers van Enerdata: € 0,058 all in voor gas en een gemiddelde jaarlijkse inflatie in België over de laatste vijf jaar van 2,85%.

In het energiemodel dat wij hanteren bleek in dit geval dat er een primaire energie van 1837 kWh per jaar nodig was. Voor de omzetting naar gas gebruiken we volgende conversie factor: 1 kWh natuurlijke gas energie = 1,1 kWh primaire energie.

Gecombineerd met bovenstaande uitgangspunten inzake LCC gaf dit een totale NPV voor de post 9C.3.3A.53.3  kosten energieverbruik in "gebruiks" toestand van € 3783,28.

In een meer pessimistisch scenario van bv. 10% inflatie m.b.t. de energieprijzen, kijken we al tegen een NPV van € 4670,82 aan of een verhoging van 23% !

Conclusie

Voor de fun heb ik bovenvermelde oefening eens gedaan voor drie scenario's:

• de optimistische kijk op de zaken: 10% reële rente, 2,85% inflatie voor energie en 2,00% inflatie voor alle andere zaken
• de realistische aanpak die wij hanteerden: 5% reële rente, 2,85% inflatie voor energie en 2,00% inflatie voor alle andere zaken
• en voor de pessimisten onder ons:  5% reële rente, 10% inflatie voor energie en 2,00% inflatie voor alle andere zaken

Als realist kwam ik tot een totale LCC voor een 120 liter spiraalboiler over een periode van 30 jaar van € 5709,69

De optimisten onder ons zullen slechts € 4750,17 of 17% minder voorzien.

En de pessimisten onder ons zullen € 6597,23 langs de kant zetten of 16% meer.

Conclusie: goede afspraken zijn een absolute voorwaarde om tot een objectieve vergelijking omtrent LCC te komen.

Ik zie jullie reacties graag tegemoet !

Vriendelijke groeten,

Peggy Bovens

www.bouwdata.net of de Linkedin group "The Art of Estimating"

(*) in ECI publicatie No Cu0106 door David Chapman (in aug 2011 gepubliceerd op www.leonardo-energy.com )
(**) prijzen exclusief BTW