SERVICE LIFE PREDICTION FOR FLOOR COVERINGS
Service life prediction for floor coverings
J. PAULSEN
Building Materials, Royal Institute of Technology, Stockholm, Sweden.
Durability of Building Materials and Components 8. (1999) Edited by M.A. Lacasse
and D.J. Vanier. Institute for Research in Construction, Ottawa ON, K1A 0R6,
Canada, pp. 1467-1474.

National Research Council Canada 1999
Abstract
A Life Cycle Assessment on floor coverings in the public and service sector is under progress in Sweden, with emphasis on the usage phase. The result is sensitive to the predicted service life and it is highly desirable with a good estimate of the actual service life. But, service life prediction for a specific type of floor covering has shown difficult. However, an important topic is to detect the relation between the type of service life and the type of premise where the floor covering is installed. Five different types of service life are suggested, and further, it is suggested that technically and aesthetically requirement play an important role, strongly influenced by the economy. The public and service sector is also divided into five different types of premises and related to the different types of service life. It is showed that the prediction of service life for floor coverings can not be done with data on floor coverings only. Further information is required concerning maintenance methods and building related data. No intentions have been made to estimate the length of the different service life.
Keywords: Floor coverings, Service life, Public sector, Life cycle assessment,
Usage phase, Swedish building stock
1 Introduction
To predict the service life for a specific type of floor covering has shown to be difficult. When a Life Cycle Assessment (LCA) has to be carried out on floor coverings with emphasis on the usage phase, one important factor is the length of the service life (Paulsen, 1998). Earlier case studies on floor coverings have shown that there are difficulties in estimating this factor (Jönsson 1994, Pottring

1993, Lundblad 1994, Günther&Langowski 1997). Rough estimates have been used. Common for those case studies is that the emphasis has been on the production stage and the waste treatment stage. The usage phase has been excluded or only briefly handled. Further, the emphasis has been on the floor covering as a material regardless of where it is placed.
A case study on floor coverings in the public and service sector in Sweden is under progress (Paulsen 1998). It is an attempt to carry out an LCA with emphasis on the usage phase. The result is sensitive to the predicted service life and it is highly desirable with a more sophisticated estimate.
Common for the floor coverings in the public and service sector is that professional cleaning companies maintain them to a large extent.
The aim of this paper is to define different types of service life for floor coverings in the Swedish building stock. Further, focus is on the premises in the public and service sector. Here the economy plays an important role and an attempt is done to describe the interrelation between the different types of service life with focus on the economy. No intention has been made to estimate the length of the different types of service life.
2 Types of service life for floor coverings in Sweden
To determine the service life for a floor covering, it is necessary to define the different types of service life times. In this paper, five different types of service life are suggested for the public and service sector (Lidström 1998,
Paulsen 1998). However, the same types of service life can be used for other parts of the building stock:
1.
Technical (functional) service life
2.
Aesthetic service life, (type 1)
3.
Aesthetic service life, (type 2)
4.
Economic service life
5.
Ecological service life
For the same application, these five service life can differ widely. One major problem is to decide which one determines the actually service life for the floor covering. In the following, a short description of the different service life is given.
2.1
Technical service life
The technical service life can be seen as the maximum service life for a floor covering. In the definition of this service life it is understood that it can not be exceeded without serious consequences. The technical service life depends on the functional demands on the floor covering. Normally, different kinds of properties and demands for a floor covering are set in relation to the actual type of premises. Demands can for example be set concerning cleanability and slipperiness etc.

2.2
Aesthetic service life, type 1
The aesthetic service life is to a large extent dependent on the form of activity in the premises in combination with trends and fashion at the current time.
The choice of aesthetic service life is based on a subjective valuation and thereby depending on individual opinions. No rules or guidelines exist to estimate the aesthetic service life. One theory is that the change of floor coverings in certain types of premises is following the change of tenant. This normally occurs when a new tenant wants to set his/her own personal expression in the premises.
2.3
Aesthetic service life, type 2 (Upgrading service life)
The upgrading service life is not a common concept but a preliminary definition to cover a situation where the floor covering is replaced because of a larger upgrading of the premises, involving more than one actor. For example, if a department store is upgraded, the floor covering is also upgraded or replaced to make an attractive environment together with the rest of the premises. It can be discussed if it shall be regarded as an aesthetic service life, but in this case the service life is decided independent of the condition of the floor covering
(Lidström 1998).
2.4
Economical service life
The economical service life is a monetary relation between the costs for maintenance at the current time and the cost for replacement of a new floor covering with reduced maintenance cost. The economical service life only exist under the assumption that maintenance cost increases in time because the floor demands an increasing maintenance with age, or because new and cheaper maintenance methods are developed which are not applicable on the current type of floor covering. There also exists a relation between the economic and aesthetic service life, which will be described later.
2.5
Ecological service life
The ecological service life is determined in the similar way as the economical service life, but with emphasis on the environmental factors such as energy use, global warming and acidification. One major problem is that the environmental impacts are a multi dimensional parameter, which is very difficult to normalize. Even the individual environmental impacts are normally hard to estimate in the present-day situation due to lack of data.
3 Dividing the premises into different types (regarding the Swedish building stock)
The Swedish building stock comprises approximately 647 million m
2
of floor covering. See table 1 (Bejrum 1997).

Table 1: Swedish building stock 1995
No Type of building
1 Houses
2 Multiple-flat buildings
3 Industry
4 Public buildings, administration
5 Offices, stores, hotels
Total
Surface
(Million m
2
)
226
154
110
85
72
647
Share
(%)
35
24
17
13
11
100
The largest group of buildings is dwelling houses (type 1 and 2 in table 1).
Here, it is very hard to categorize the aspects or valuations, which is fundamental for the determination of the service life. The actors in this group are nonhomogenous, with a broad range of individual opinions about requirements on performances concerning floor coverings.
For the industrial sector (type 3 in table 1), it can be expected that the requirements are high on the technical performance while the aesthetic aspects have a lower priority.
In the public and service sector (type 4 and 5 in table 1), large expenses are connected with the maintenance compared to buying and installation of new floor coverings. Here it can be expected that the economical service life have a dominant influence. Table 2 shows Swedish trade figures (1995) for floor coverings to illustrate the investment costs (GBR 1996).
Table 2: Investment costs (incl. installation) for 23 million m
2
floor coverings
Resilient floor coverings
Installation
Total
Trade in Sweden 1995
(million SEK)
3,000
700
3,700
Average costs per m
2
(SEK)
130
30
160
In Sweden, the maintained surface for the public and service sector was 150
2 million m floor covering in 1996. The costs for cleaning were 17,000 million
SEK. (SG 1997). A good estimate is that around 70% of the cleaning costs are related to the floor covering. This gives an average cost of approximately 80 SEK
2 per m a year. In relation to the investment cost for a new floor covering, the maintenance costs are considerable. In other words it can be said, “It is quite
cheap to buy a floor covering, but expensive to own it” (Forslöw 1989).
The public and service sectors (type 4 and 5 in table 1) represent approximately 24% of the Swedish building stock. Unfortunately, no inventory data exists concerning the areas for a further sub grouping into premise types
(Laurila 1998). However it is desirable to make a new grouping for these premises and their relation to the type of decisive service life to support the LCA study mentioned earlier (Paulsen 1998). A suggestion is given in table 3 (Lidström
1998; Franzén 1998).

Table 3: Type of service life related to type of premise in the public and service sector
Type of premises
Schools
Department stores
Hospitals
Offices (private)
Offices (public)
Total (approximately)
Type of service life Area in million m
2
Technical
Aesthetic type 2
Technical
Aesthetic type 1
Technical
----
No data
No data
No data
No data
No data
150
4 Interrelation between the different types of service life times
It is doubtful if the different types of service life times can be considered as independent of each other. For premises in the public and service sector, it has earlier been suggested that the economy is a very dominant factor. For these types of premises it would be interesting to discuss the interrelation between the different kinds of service life.
In figure 1, a suggestion is given to describe how the economy influences the different types of service life in the public and service sector.
Ecological
lifetime
Technical
lifetime
Type of premises
Schools
Hospitals
Public offices
Economic lifetime
Aesthetic lifetime
type 1
Aesthetic lifetime type 2
Type of premises
(single decision makers)
Private offices
Hotels
Type of premises
(several decision makers)
Department stores
Fig. 1: Economic influence on service life
As illustrated in figure 1, the economic service life can be expected to play an important role.
For schools, hospitals and public offices, the technical service life can be considered as the determining factor. However, the economy plays a considerable

role because one of the most important technical demands on this kind of floor covering is that it is easy to clean. Indirectly, this is an economic demand, because the costs for cleaning are strongly dependent on the time required for cleaning the surface. Parallel to economic aspects, the ecologically aspects can be considered.
Unfortunately the foundation for this is not yet properly developed concerning the usage phase (Paulsen 1998).
For private offices and hotels, the aesthetic service life (type 1) normally can be considered as the determining factor. Nevertheless, this can also be considered as an indirect economical service life. In this kind of premise, the image is an important function for the floor covering. The aesthetic service life
(type 1) can be set in relation to the market value of the premise. If the floor covering does not satisfy the customer's demands on aesthetics, the premises no longer preserve the possible market value, and thereby the aesthetic service life for the floor covering can indirectly be seen as an economical service life. The aesthetic service life could be assumed to be strongly connected to the change of tenant.
Service life in department stores can be more complicated to determine. In this paper the service life is suggested to be dependent on aesthetic aspects.
Similar to the private offices and hotels, the aesthetics is an important function for the floor covering. Also there is a strong interrelation with economic aspects. The premises have to be attractive for the tenants. However, here the situation differs from hotels and private offices in an important issue: in a department store, several actors have to accept an aesthetic level, which is acceptable for the majority.
As suggested here, it seems possible that the service life is dependent on a common decision by several actors, with primary focus on the premises as a whole and not only the state of the floor covering.
For the premises with the two described types of aesthetic service life, it seems difficult to express ecological aspects parallel to the economic aspects. In that case, the value should lay in the value of an environmental profile for the tenant in the premises.
5 Factors influencing the service life in the public and service sector
As earlier mentioned, different types of service life can be related to different types of premises in the public and service sector. Important topics are technical and aesthetic demands, influenced directly or indirectly by the economy.
However, both technical and aesthetic performances are further influenced by other factors (GBR recommendations 1996). Three main factors are properties of the floor covering, maintenance methods and building related factors. Those will be described further in the following.

5.1
Floor covering related factors
5.1.1
Technical product properties
Different kinds of floor covering have different kinds of properties concerning the wear-layer thickness, resistance to wearing, etc. which all give information about circumstances affecting the life time. The main part of floor covering types can be divided into different types of wear classes, with information about appropriate type of premises.
By installation of a material (floor covering) with a higher wear-class than the premise demands, the service life can be extended (and vice versa).
5.1.2
Upgrading
Some kinds of floor covering can be upgraded, when the wear has destroyed the technical or aesthetic function. Wood and linoleum floorings can be grinded and surface treated. Polyurethane (PUR) layers on plastic coverings can be renovated and pieces of coverings can be replaced. In that way, a floor covering can achieve a considerable extension of the service life.
5.2
Maintenance
Correct care and maintenance, are prerequisites for a long service life for the floor covering. Incorrect maintenance can damage the floor covering in only a few months. Further, the periodical maintenance can protect the floor covering against wearing, and reduce the frequent cleaning costs.
5.3
Building related factors
5.3.1
Location in the building
On ground level the wear of floor covering is larger than higher up in the building, which demands a hardwearing floor covering and more intensive care.
The wear on floor coverings also varies considerably over the floor surface. In door openings and walk-traffic intensive areas, the wear is much larger than e.g.
in corners.
5.3.2
Design of the entrance
Correct performance of wipe-off zone in the entrance is a very important factor concerning the service life for floor coverings.
5.3.3
Traffic intensity and type of load
In an office building the service life of a floor covering is shorter in a corridor than inside an office, if the same type of covering is used in both places.
5.3.4
Geographical location of the building
The geographical location of the building also plays an important role. The outdoor environment will to a large extend influence the amount and type of dirt in the building. However, here it is important to analyze this topic in combination with the design of the entrance.

6 Discussion and conclusions
As described above, it is almost impossible to predict the service life of a floor covering only considering the floor materials. Nevertheless, when the application is known the range of information increase and a better estimate can be done.
This paper suggests several relations between the required type of service life for floor coverings and the type of premise. For premises in the service and public sector, the economic aspects can be expected to have a strong influence when attempts are done to predict the service life. This is due to the fact that the maintenance costs are very high compared to the investment costs for new floor coverings. The maintenance costs are approximately higher for two years of maintenance than the investment costs for a new floor covering.
Technical requirements often reflect the demands on low maintenance costs, and aesthetic demands often reflect the premises economical market value.
Ecological service life for floor coverings can theoretically be calculated and regarded similar to the economical aspects for floor covering, but the foundation has not yet been properly developed.
7 References
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Franzén, T. (1998) Partena AB, (Swedish cleaning company) personal communication.
Forslöw, G (1989) Maintenance costs for floor coverings. Golvets driftsekonomi
In Swedish, Tarkett
GBR. (1996), Swedish branch organization for floor coverings, Golvbranschens
riksorganisation, Golvtekniska pärmen. In Swedish, technical report.
Gunther, A and Langowski, H (1997) LCA study on resilient floor coverings. The
International journal of Life Cycle Assessment, vol. 2, No. 2. pp 73-80
Jönnson, Å. (1995) Life cycle assessment on flooring materials, Licentiate thesis,
CTH, Sweden
Laurila, J: (1998) SCB, Statistic Sweden (Statistiska Centralbyrån) personal communication.
Lidström, R. (1998):ISS, Sweden AB, (Swedish cleaning company) personal communication.
Lundblad, D: (1994) Environmental impacts from maintenance of floor coverings
(Miljöpåverkan av golvvård) In Swedish, KTH, Trita-Byma 1994:7
Paulsen, J. (1998) Life Cycle Impact of Floor Coverings-A Model for the
Contribution of the Usage Phase, proceedings of the CIB World Building
Congress Gävle 1998
Pottring, J. (1993) The environmental life cycle analysis of some floor coverings,
1993, Journal of cleaner production, vol. 3, No 4.
SG (1997) Swedish council of floor materials and floor maintenance (Svenska golvrådet, DUS A flik 8) In Swedish, Trade statistics.