Aging and temperature dependency of acoustic PVC floor covering under French certification NF UPEC.A+

Transcription

1 Edinburgh, Scotland EURONOISE 2009 October Aging and temperature dependency of acoustic PVC floor covering under French certification NF UPEC.A+ Jean-Baptiste Chéné a Rémy Foret b Paris-Est University, Center for Building Science and Technology (CSTB) 84, Avenue Jean Jaurès Champs sur Marne Marne La Vallée Cedex 2, France Claude Martin c Catherine Guigou-Carter d Michel Villot e Paris-Est University, Center for Building Science and Technology (CSTB) 24 Rue Joseph Fourier Saint Martin d Hères, France ABSTRACT France like some European countries takes into account intrinsic acoustic performance of floor coverings to reach building regulation requirements in terms of impact noise level. In this context PVC floor covering market developed in France yielding to the performance certification of these products under the label UPECA+ about ten years ago. The concerned industrials gathered within the SFEC (Syndicat Français des Enducteurs Calandreurs) anxious to answer market questionings about the time durability of their performances launched a wide study on the subject in collaboration with the CSTB and the support of the DGUHC (housing ministry). Six products have been followed during five years both in laboratory (natural aging without particular promptings) and in-situ (two livedin housings). Intermediate observations of in-situ measurements campaigns led us to complete these investigations by a study on temperature base floor impact on acoustic performances. The main results are the time stability of acoustic performances of certified products as well as their strong dependency on surface base floor temperature. 1. INTRODUCTION The French regulation based on results requirements allows taking into account the floor covering performance to reach the required impact noise level (L nt,w 58 db in the new housing building and 60 db for hostelry, health and scholar buildings). Due this specificity, not only French, a certain number of solutions and particularly soft PVC floor coverings emerged. These ones allow a strong optimization of the building that can avoid the use of heavy solutions like floating floors, which represents a financial, mounting time and space gain (7 to 10 cm high by stair) as well as strongly decreasing the mounting difficulties a address. jean-baptiste.chene@cstb.fr b address. remy.foret@cstb.fr c address. claude.martin@cstb.fr d address. catherine.guigou@cstb.fr e address. michel.villot@cstb.fr

2 encountered with floating floor system; these coverings also have equivalent acoustic performances than concrete screed on thin resilient layer systems (15 db L w 21dB for resilient PVC floor coverings and 17 db L w 22dB for floating floor on continuous resilient layers). The quick development of these products raised some questions, first for an industrial to manufacture these products with a constant acoustic performance. In order to answer to these questions the main companies of the domain, gathered within the SFEC union ( Syndicat Français des Enducteurs Calandreurs ), set up a quality mark NF UPEC A with the CSTB, this one assures that the improvement to impact noise level L w of the products as well as their fitness for purpose ( L w measured in CSTB laboratory every 3 years and L w measured as production controls in factories every m² of manufacturing, it represents 1000 tests per year for some companies in their own laboratory). After 10 years of NF UPEC A mark existence, it is a recognized fact that manufacturers can guarantee a constancy in the production, but in a parallel way the time durability of the acoustic performance of these products was brought up. Therefore, CSTB was commissioned by the SFEC, helped by the DGUHC to carry out a long-term investigation on the acoustic behaviour of these products. Thus, the acoustic behaviour of six PVC floor coverings has been overseen during five years in three different configurations, the first one in our acoustic tests laboratory (LABE), the second one in a housing building in Reims and the last one in a meeting room in Saint Martin d Hères. These investigation results are presented hereafter, based on an experimental approach in two steps, the first one concerning the acoustic behaviour of the products over time and the second one about their dependency of floor temperature. 2. ACOUSTIC AGING OF PVC FLOOR COVERING Six samples were selected in order to cover the acoustic performance range of certified products NF UPEC A as well as the different technologies used to reach them. The whole measurements were carried out on products from the same manufacturing batch. Both insitu tests environments were selected in function of their purpose in order to have different promptings (housing for the site of Reims and meeting room for the CSTB site at Saint Martin d Hères). A. Description of the different floor covering Five of the six floor coverings have similar structures, it means PVC layer on foam in accordance with the product Standard EN 651. Only the product #4 is a cork-based PVC floor covering that fits the product Standard EN 652. Table 1: Initial performance of the six NF UPEC A* certified products Improvement of impact UPEC* Class Product # sound insulation (bonded laying) L w in db 1 17 U3 P U3 P U2S P U2S P U2S P U3 P3 (*) The UPEC class corresponds to different purpose parameters of these floor coverings (U: worn state to walk; P: clipping; E: water behaviour; C: resistance to stains and chemical agents; A: acoustics L w ; soon A+ : acoustics L w + walking noise)

3 B. Description and results in laboratory The measurement were carried out at the LABE, acoustics tests laboratory of the CSTB, accredited ISO by the COFRAC organism and in particular for floor covering tests in accordance with the Standard NF EN ISO (improvement to impact sound insulation L w assessment). The same three samples (35x60 cm) of each six products were bonded with maintain glue one time a year in our laboratory on a 14 cm thick concrete base floor (19 C temperature of the floor surface 23 C). Between two measurements, the samples were stocked being sheltered from humidity, temperature and UVs. This is the natural aging of these products that we try to investigate. Product # Table 2: Laboratory performances of six floor coverings within a 5 years period time. Improvement to impact sound insulation L w en db Figure 1: L w of the product #1 (left plot) and #4 (right plot) between 2003 and 2007.

4 In the table 2 that tabulates the evolution of the results between 2003 and 2007, we can notice a stability of the performances, only one of the products has a variation higher than 1 db. It can also be underlined that these variations do not correspond to a performance loss over time since, apart from the product #1 (1 db less), the obtained performance in 2007 is similar to Lastly, there are no particular trends to note between the two different structures of PVC floor coverings (EN 561 and EN 562). The L w curves presented in the Figure 1 show small variations in terms of frequency, near uncertainties of reproducibility in the laboratory for this type of test. C. Description and results in field measurements Two sites have been followed, the first one was a meeting room of the CSTB at Saint Martin d Hères site, and the floor of this room was a coffered concrete slab. It was divided into six identical areas, each one covered by a different PVC floor covering (Figure 2). During each tests campaign, three positions of ISO tapping machine were measured for each floor covering. These positions were the same for the five years tests campaign. Figure 2: Meeting room floor covered by the six PVC floor coverings. There is no difference over time between the three tested positions for each floor covering. The presented results, are so an average of these positions for each product C C 23 C L'ntw in db product 1 product 2 product 3 product 4 product 5 product 6 Average 24 C C 47 Aug-03 Feb-04 Aug-04 Feb-05 Aug-05 Feb-06 Aug-06 Feb-07 Aug-07 Feb C 32 C Figure 3: L nt,w variation at the Saint Martin d Hères site for the six PVC floor coverings between 2003 in 2007.

5 In August 2004, the cyclical behaviour of the performance of the L nt,w begins to be obvious, with a L nt,w minimum in summer and maximum in winter. The temperature of the floor seemed to significantly influence the results; it yields the measurement of the base floor temperature since February 2005 and for the end of the campaign. Furthermore, the first measurement point on the Figure 3, carried out in August 2003, shows a very low L nt,w value since a heatwave in France has been going on for 2 months. It can explain the abnormally low impact noise level against the other measurements; unfortunately the temperature of the base floor has not been picked out during these first tests campaigns. The second site which has been overseen is a small dwellings building located in Reims. The access conditions in these occupied dwellings being difficult, only one campaign per year was carried out. Table 2: Acoustic performances of five of the six products on the Reims site. Product # Measurements: L nt,w in db Regulation objectives: L nt,w in db 11/09/07 13/09/06 13/09/05 08/09/04 27/07/ to to to to to * 48 to 49* 48* 49 to 52* to to to to to to to to to to to to to to to to to * in 2004 a suspended ceiling was mounted in the reception room. The data presented in the Table 3 show that the tendencies are quite similar although reduced in comparison with the ones measured on the Saint Martin d Hères site. One explanation of this phenomenon is presented in 3.B. D. Conclusions on the acoustic aging of PVC floor covering The underlined variations in the different investigations seem to be cyclical and mainly linked to the temperature of the base floor. No particular alteration of the improvement to impact noise level can be observed during the five years that this campaign lasted. It needs to be moderated by the fact that the temperature measurements only began in 2005, thus it is difficult to apprehend the 2003 heatwave impact. In order to achieve a better understanding of this dependency, CSTB launched, with the support of the SFEC union and the DGUHC, an additional investigation in laboratory on this topic.

6 3. TEMPERATURE DEPENDENCY OF THE ACOUSTIC PERFORMANCE OF PVC FLOOR COVERING A. Laboratory evaluation of this effect In order to study this dependency, three of the six floor coverings of the previous investigation presented in 2 were selected (product #1, #2 and #4). This step occurred in the same laboratory that described in paragraph 2.B, the temperature of the base floor has been varied between 12 C and 27 C. Figure 4: L w variation of PVC floor covering #1 (left plot), #2 (centre plot) and #4 (right plot) in function of the temperature of the concrete base floor. The noticed variations are significant, they go from 3 db for the product #1 to 1 db for the product #It is interesting to remark that the temperature dependency does not seem to be linked to the covering structure, since the floor covering #4 being the only one to have cork, has an intermediate behaviour (in between product #1 and #2). Moreover, it does not seem to be linked to a performance level ( L w ) indeed product #2 which is the most effective only undergoes a 1 db variation on the range C whereas the less effective product (product #4) undergoes a 2 db change and the product #3 (having an intermediate performance) has 1 db change on the same temperature range. B. Complementary analysis of the influence of temperature on in-site measurements The observed trends on the Figure 4 are similar to those observed in laboratory, the product hierarchy in terms of stability is close, however the magnitudes are higher in-situ (in Saint Martin d Hères) than in laboratory (Table 4). Table 4: Comparison of acoustic performance variations between two temperatures of floor, both in-situ and in laboratory. Product # (L ntw ) en db, in-situ measurements in Saint Martin d Hères between February 2005 (floor at 19 C) and August 2005 (floor at 26 C) ( L w ) in db, laboratory measurements between the floor at 20 C and 27 C

7 As mentioned in 2.C, the measurements on the Reims site present the same tendency than the Saint Martin d Hères measurements, but with less amplitude. It can be explained by two main differences between the sites. The first one corresponds to the type and age of the building. Indeed, the Reims building, devoted to dwellings and recently built (2003) is correctly thermally insulated (in accordance 2000 Thermal Regulation) and having thick concrete floors (18-20 cm) which bring a good thermal inertia. On the contrary, the Saint Martin d Hères building is dated from 70 s period; it has low thermal properties and low thickness concrete floors (approximately twice lower than Reims floors) without being airconditioned. It has also large and wide glazing units on two sides, which expose certain areas to a specific sunshine. The second explanation may be the weather conditions of the sites. Indeed the temperature variation in August in Reims (max. average temperature for one month) over the five years study was of 6.6 C whereas on the Saint Martin d Hères site (here assimilated to Grenoble) was of 8.9 C (see Table 5). These differences between these two sites (building configuration and ambient temperature) explain a priori the largest amplitude variations on the Grenoble site. In order to achieve a better understanding of measures made in August 2003 in the Saint Martin d Hères site, although the temperature floor was not measured at this time, a temperature research for August month between 2003 and 2007 had been carried out and is presented in Table 5. By comparing these temperatures with ones of floor, it turns out that the maximal average temperature for one month is quite the same than the floor. By extrapolation, it is plausible that the floor temperature was close to 33 C in In September 2007, in addition to the laboratory investigations on floor temperature, a test was carried out in Saint Martin d Hères by warming up to 32 C the floor, this measure corresponds to the last marks of Figure 3. We state that the measured L nt,w is 1 db different in average from the 2003 measurement for the six coverings. It confirms that the low measurements values during the August 2003 test campaign are connected to heatwave that France undergone this summer Table 5: Comparison of Grenoble and Saint Martin ambient temperatures in August between 2003 and Month Max. average Base floor temperature during Maximal temperature T temperature T in C the tests T at Saint Martin in C at Grenoble * at Grenoble* d Hères August (28.7**) 39.5 (39.3**) - August (25.3**) 35.3 (34.5**) - August (23.1**) 32.2 (32.2**) 26 August (21.1**) 29.2 (25.8**) 26 August (22.1**) 33.2 (32.3**) 24 (*) Source Grenoble is the nearest weather station from Saint Martin d Hères. (**) Data for the Reims city. C. Conclusion on the temperature dependency of the acoustic performance of PVC floor covering The influence of the base floor temperature on the acoustic performance has been demonstrated for both in-situ and laboratory measurements. If one could expect this phenomenon, the magnitude of the latter shall be reminded both for laboratory assessment and at the delivery of a building equipped with PVC floor covering. Indeed regulatory control measurement of a building in winter, before its service, on a shadowed area of the floor with a surface at about 10 C or the same measure made in summer on a sunny area with floor temperature nearby C, the L nt,w differences will going to be close to 10 db for some products.

8 4. CONCLUSIONS This extended scope investigation in terms of time length allows showing the nondegradation over time of acoustic performances of PVC floor coverings, at least for a 5 years period time. The changing period of these coverings being about every 10 years, and in regards to the small performance change over 5 years, there are strong chances that these products do not show alteration of their acoustic performances during their nominal use. On the other hand, the acoustic issue lies at the moment of replacing the floor covering if this one is replaced by a non-acoustic product, it is a priori the main drawback of French system. These test campaigns allow demonstrating the strong temperature dependency of the base floor. On the one hand, the acoustic test laboratories have to be warned of this dependency so as they measure and handle the base floor temperature during these tests. On the other hand, the persons in charge of the in-situ measurements have to be careful with their acoustic assessment by taking into consideration the temperature of the base floor, the ISO tapping machine positions (sunshine exposure areas) and the time period control (before or after the housing service). Lastly, if this range of products has a strong dependency of temperature, it seems consistent to question over this influence on other products like closed cells foams (polyethylene foam ) used for floating floors. New investigations seem to be necessary. ACKNOWLEDGMENTS The authors gratefully acknowledge the financial support of this work provided by the French Ministery of Housing and the French industrial union of undercoating calendering SFEC Syndicat français des enducteurs calandreurs. REFERENCES 1. NF EN ISO 140-8, Acoustics Measurement of sound insulation in buildings and of building elements Part 8: Laboratory measurements of the reduction of transmitted impact noise by floor coverings on a heavyweight standard floor, (1997) 2. NF EN ISO 140-7, Acoustics Measurement of sound insulation in buildings and of building elements Part 7: Field measurements of impact sound insulation of floors (1998) 3. Certification rules NF UPEC A