Contractor

Name : Rectorat de Mayotte

Contact : Blaise Tricon : blaise.tricon[a]ac-mayotte.fr

 http://www.ac-mayotte.fr/

Construction Manager

Name : LAB Réunion - 2APMR mandataires

Contact : Antoine Perrau ap[a]labreunion.fr

 https://labreunion.fr/

Stakeholders

Function : Designer

Tand'M

Stéphan Aimé

project management

Function : Structures calculist

GECP & OMNIS

Alexandre Jennant

structural and seismic studies

Function : Other consultancy agency

INSET

Eric Ottenwelter

Fluid study and BET

Function : Thermal consultancy agency

LEU Réunion

Simon Chauvat

 https://www.leureunion.fr/


Thermal design office, QE, landscape

Function : Structures calculist

I2M

Jean Marc Bouchut

bet metal structure

Function : Other consultancy agency

NATURALISTE DE MAYOTTE

Franck Coudray

Naturalist

Function : Company

SOGEA TRAVAUX

Claude Petit

external development company

Function : Company

SMTPC

Olivier Trassard

masonry structural work

Function : Company

SMAC

Virgile Virot

metal structure company - cladding - metal textile

Function : Other consultancy agency

Delhome acoustique

bet acoustic studies

Function : Other consultancy agency

MBE

ANtoine Bajeux

bet vrd

Function : Construction Manager

Michel Delafosse

Michel Delafosse

project manager and OPC

Type of market

Global performance contract

Energy consumption

• Primary energy need : 90,00 kWhep/m².an
• Primary energy need for standard building : 330,00 kWhep/m².an

Calculation method : RTAA DOM 2012

Breakdown for energy consumption : Outdoor lighting: 7,305 kWh Interior lighting: 21,448 kWh Air conditioning: 9556 kWh CMV: 592 kWh Kitchen ventilation: 1082 kWh Elevator: 400kWh Ventilators: 14,990 kWh Hot water: 1000 kWh Restoration: 120,000kWh Miscellaneous: 15,000 kWh

Real final energy consumption

Final Energy : 27,00 kWhef/m².an

More information

Interior lighting expansion of 0.8 Standard building ratio 100 kWh / m²SU / year

Systems

Heating system :
• No heating system
Hot water system :
• Solar Thermal
Cooling system :
• Water chiller
• Fan coil
Ventilation system :
• Natural ventilation
Renewable systems :
• Solar Thermal

The project of a photovoltaic farm on the roof is under study, it should enable the objective of a positive energy building to be achieved.

Smart Building

Users’ opinion on the Smart Building functions :

 

 

Urban environment

• Land plot area : 34 443,00 m²
• Green space : 19 125,00

From the start, the philosophy behind our concept has been that of minimal impact, both visual and physical, on the site. To do this, we have organized a project deploying in a flexible way along the contour lines optimizing the movements of the earth. This choice was amended and reinforced by the desire to preserve the remarkable trees punctuating this site, the two baobabs and the orchard of fruit trees in particular.

The need to ensure optimal ventilation of the premises to ensure thermal comfort has also dictated specific morphologies of the building, low thickness of the constructive framework, construction on stilts optimizing air circulation, single-slope roofs, patios with low pressure wells, optimizing the phenomena of pressure / depression, orientation of the North-South frame ideal for solar protection and side lighting in classrooms.

Finally, the desire to preserve ecological corridors and good hydraulic transparency, led us to build on stilts and to make breaks ensuring the free flow of rainwater on the surface in the existing thalwegs, thus limiting the acceleration of runoff and the erosion of so fragile soils in Mayotte.

 

Insertion into the site

At the convergence of the architectural and environmental quality concerns mentioned above, the quality of insertion is thus easily ensured by a minimal impact, a split project, on the slope, in preserved vegetation. It is a question here of making a public facility coiled in the slopes and the vegetation preserving as much as possible a majestic site of the perfume island.

The insertion in the site is worked strongly with in particular:

• a tier in the slope of the highest volumes
• a tiering of living terraces, with sets of ramps becoming spaces for development complementary to the large spaces of the courtyard
• the conservation of large native (baobab) and domestic (mango) trees in order to benefit from shade and participate in the registration plenum on the slope
• simple volumes with roofs following the slope for the highest (cumulative aerodynamic effect and insertion)
• the plant enhancement of the site with in particular the creation of forest gardens in native biodiversity (potentially conservatory site) forming a setting and continuity with the slope of the large landscape
• soft treatment of rainwater flows (conservation of small valleys, decontaminating aerial management of rainwater)

 

Product

COVERIB

ONDULIT

Laurent Pippinato

 https://ondulit.com/


Product category : Gros œuvre / Charpente, couverture, étanchéité

Multilayer roofing with high performance: sound insulation (noise impact of rain), high solar reflection power

No specific problem

SMC2



SMC2

Samuel Guillermard

 https://www.smc2-construction.com/


Product category : Gros œuvre / Charpente, couverture, étanchéité

Metallo-textile framework with prestressed PVC type text and tensioning system by mechanical jacks.

Very good feedback, provides sun protection and homogeneous light for sports practice at a very good value for money.

Crystalis transparent roller shutter

 https://www.provelis.com/nouveautes/le-volet-roulant-transparent/


Product category : Second œuvre / Menuiseries extérieures

Transparent roller shutter used in classroom glazing allowing full opening and therefore excellent natural ventilation (maximum porosity).

No specific problem reported.

Construction and exploitation costs

• Total cost of the building : 24 730 000 €

Water management

• Consumption from water network : 261 573,00 m³

Water Consumption/m2 : 47.25

Water Consumption/Pupil : 290.64

Water tarpaulins have been put in place to collect rainwater to supply the toilets. This device makes it possible to deal with frequent water cuts on the site.

Rainy waters :
On-site rainwater management is managed gently and on the plot. Thus, rainwater delay / infiltration devices have been installed on the site. We thus find, as we can see in the ground plan below, landscape valleys around the buildings and in the lower parts of the plot.

Vegetated valleys are structures that collect and regulate rainwater and runoff by slowing its flow to an outlet. This type of technique is suitable for the management of rainwater for the Bouéni college construction project in Mayotte.
From a technical point of view, the green valleys are structured in this way:

The permeability of a plot is the ability of the land to delay and infiltrate rainwater. Thus, a so-called “permeable” soil will have a greater capacity to manage rainwater on site (greater storage / infiltration volume). A permeable soil is characterized by the nature of its coating. Thus, a concrete surface will be impermeable (coefficient of permeability = 0) unlike a surface with several plant layers (coefficient of permeability = 1).

Permeability
FLOOR COVERING Surface in m² Percentage (%) Coefficient Result
Concrete swept on roadway and access 1,300 / 2.9% / 0.00
Pedestrian swept concrete 2,200 / 5.0% / 0.00
Concrete grass slab 900 / 2.0% / 0.00
Flat stone paving 1,020 / 2.3% / 0.00
Grating 60 / 0.1% / 0.318
High Modulus Asphalt 1,280 / 2.9% / 0.00
Bituminous concrete 6 9,401 / 5.6% / 0.00
Colored bituminous concrete 1720 / 3.9% / 0.00
Concrete stairs 410 / 0.9% / 0.00

BUILDINGS
Overall (Right-of-way built on the ground floor, excluding roof terraces) 3,427 / 7.7% / 0.00
Green roof terrace 823 / 1.9% / 0.3247

PLANT SYSTEMS
SV1 Forest gardens 19 3954 / 3.7% / 1.019 395
SV2 Courtyard Gardens 667 / 1.5% / 1.0667
Planting pit - trees in the yard 15 / 0.0% / 1.015

Project 44 40 710/0% 46%

The plot's waterproofing coefficient is 54%, which is correct.


Drinking water consumption
Consumption item Ratio Area (m²) Daily consumption (liters) Annual consumption (liters)
Flush / 4.5 liters / uses1 200 300,000
Sanitary water (maintenance, hand washing, etc.) 1 liters / day / person 1200 300 000
Catering 4000 liters / day 40001000000
Forest gardens 2 liters / m² / day 193953879014158350
Courtyard gardens 5 liters / m² / day 66733351217275

TOTAL WATER CONSUMPTION: 19,078,025
TOTAL WATER CONSUMPTION: 26,157 m3 / year
WATER CONSUMPTION COST: € 57,806 / year
Assumption: average cost of water in Mayotte: 3.03 € / m3
The project will therefore have a drinking water consumption of 26.157m3 / year.
Note that this applies for the first year of operation because the young plantations must be sufficiently fed to be able to develop sustainably. Ultimately, consumption may be lowered.

Indoor Air quality

The concept of a building with natural comfort ventilation (only the administrative building is air-conditioned) provides excellent air quality. Simulations in a physical wind tunnel at the Eiffel laboratory in Paris rely on minimum air renewal rates of 15vol / hour ensuring excellent air quality by evacuating pollutants efficiently.

Comfort

Health & comfort :

Below is a summary table of the materials used:

Materials / Use / Description / Proliferation of microorganisms / Emissions of VOCs, toxics, allergens, etc. / Emissions of fibers and particles / Environmental certification / Ventilation conditions

Hot-dip galvanized steel, Frame, Technical room doors, Inert material, Inert material, None, Strongly ventilated, Prestressed PVC, Sun protection

Textile membrane on galvanized steel frame Null

Presence of phthalates

VOC Emissions: None

Strongly ventilated

Aluminum

Transom and spandrel

Composite panels

Nothing

Inert material

Nothing

Strongly ventilated

Polyethylene

Transom and spandrel

Composite panels

Possibility of proliferation of microorganisms if infiltration

Low quantity VOC emissions

Nothing

Not ventilated

Polycarbonate

Vertical berries

Roller shutter

Nothing

VOC emissions

Nothing

Strongly ventilated

Electro galvanized steel sheet

blanket

Nothing

Inert material

Nothing

Strongly ventilated

Mineral wool

Transom and spandrel

Lining partitions and suspended ceilings

Possibility of proliferation of microorganisms if infiltration

Low quantity VOC emissions

Emission of fine particles possible

Obligation to have an FDES

Not ventilated

Saniclip - Comepal

Sanitary separations

Compact laminate

Possibility of proliferation of microorganisms

Low quantity VOC emissions

Emission of fine particles possible

Moderately or heavily ventilated

Plaster

Partitions and lining

Possibility of proliferation of microorganisms if infiltration

Low quantity VOC emissions

Emission of fine particles possible

Moderately ventilated

Concrete

Vertical walls and slabs

nothing

Low quantity VOC emissions (grinding agents, additives, molding agents)

Nothing

Strongly ventilated

Softwood fibers

Roof insulation (thermal and acoustic)

Fiberboards (fibralith)

Possibility of proliferation of microorganisms if infiltration

Low quantity VOC emissions

Emission of fine particles possible

Acermi

NF EN

Not ventilated

Mineral fiber

Ceiling

Ceiling of the kitchen preparation area

Possibility of proliferation of micro-organisms if infiltration, VOC emissions in small quantities, Possible fine particle emissions, Not ventilated, Paint

-

Masonry and plaster walls, Nil, Low quantity VOC emissions, Nil

European eco-label, Moderately ventilated, Earthenware, Protection of walls (housing), Inert material

Inert material, Null, Glue with NaturePlus label, Moderately ventilated, Structured porcelain stoneware, Floor, Kitchen preparation area, Inert material, Inert material, Nil, Glue with NaturePlus label, Moderately ventilated

Acoustic comfort :

Acoustics :

In this part we will study the acoustic behavior of each room, by determining the indices of attenuation of the walls, the acoustic isolations between rooms and the reverberation time of the rooms.

It should be noted that in the vicinity of the project, no source of external nuisance has been detected.

Definitions of the acoustic concepts used:

Sound is a wave of energy that travels through the air more or less quickly. Depending on its intensity, it can make certain bodies vibrate and thus be transmitted through the air as well as through solid elements, such as the walls of a building. Thus, when a sound is emitted outside a room, it can be heard inside it depending on the intensity of the sound, but also depending on the physical properties of the separating walls.

Sound reduction index of a separating wall

The sound reduction index, noted R, allows to characterize the ability of the partition wall to attenuate the transmission of noise. The higher its value, the more the wall attenuates the sound level of noise transmitted.

We will focus here on the sound attenuation index weighted for a pink noise and for a traffic noise.

Acoustic insulation:

The sound insulation of a room is the arithmetic difference in sound pressure levels between the room where the sound is emitted and the room where it is received and is expressed in dB.

We are interested here particularly in the standardized sound insulation weighted DnT,A which corresponds to the sound insulation to airborne sound between two premises, taking into account the reverberation time of the room of reception.

With         

- Rw + C is the attenuation index of the separating wall;

- V the volume of the room studied;

- S is the surface of the separating wall common to the transmitting and receiving rooms (room under study and adjacent room);

- a, a corrective coefficient characterizing the decrease of the insulation due to lateral transmissions.
 

Reverberation time

Reverberation time is defined as the time in seconds that it takes for the sound to become one millionth of its original intensity (60 dB decrease in intensity level). It can be assimilated to the presence of an echo inside a room. This is regulated in educational premises by the decree of 25 April 2003, relating to the limitation of noise in educational premises.

Speech intelligibility

Speech intelligibility is defined as the ability of a monologue or conversation to be understood by a listener located nearby. This depends on the ambient noise level, the absorption of part of the sound spectrum by the walls, acoustic distortions, etc...

Standardized acoustic insulation weighted to airborne sound DnT,A and DnT,A,tr :

The sound insulation levels indicated are expressed in dB from the weighted standardized insulation DnT,W. This notation means that the difference in sound pressure levels measured in octave or third octave bands between two adjacent or overlapping rooms must be corrected for the nominal reverberation time of the receiving room.

Standardized Impact Sound Pressure Levels:

The isolations from impact noise due to walking or solidian excitations by the feet of furniture are expressed as a maximum standardized sound level not to exceed L'nT,w, calculated according to NF EN ISO 717-2, when the standardized impact machine excites the floor considered. This sound level is corrected according to the nominal reverberation time of the measuring room.

 

In the context of the middle school of BOUENI, this concept takes all its direction in particular for the classrooms, but also for the CDI. The uses being appreciably different, the expected level of acoustic comfort is different:

- in the classrooms, the teacher must be heard by all the students, whatever his position in the room, without encouraging echoes;

- In the CDI, which is not intended for verbal exchange, the acoustic level must be controlled, ensuring that users have a calm working space.

 

Acoustic regulations

The order of April 25, 2003 relating to the limitation of noise in educational establishments.

Article 2:

Here is the table of minimum values of standardized sound insulation weighted DnT,A between premises, expressed in decibels:   

ROOM OF EMISSION ROOM OF RECEPTION

teaching room, practical activities, administration

MEDICAL ROOM, infirmary, low-noise workshop, kitchen, closed assembly room, meeting room, sanitary facilities

stairwell

horizontal circulation, closed checkroom

music room, multipurpose room, sports room

catering room

Noisy WORKSHOP (as defined in section 8 of this order)

Teaching room, practical activities, administration, library, CDI, music room, meeting room, teachers' room, low-noise workshop.

Medical room, infirmary.

43 (1)

50

43

40

53

53

55

Multipurpose room.

40

50

43

30

50

50

50

Catering room

40

50 (2)

43

30

50

 

55

(1) An insulation of 40 dB is allowed in the presence of one or more communication doors. (2) With the exception of a kitchen communicating with the dining room.

Article 3:

On the other hand, Article 3 states that the weighted depression level of the standardized impact noise L'n,Tw shall not exceed 60dB. If the shocks are produced in a noisy workshop, a sports hall, the values of weighted pressure level of the noise of standardized shock, L' nT,w, must be lower than 45 dB in the rooms of reception.

Article 4:

The value of the standardized sound pressure level LnAT of noise generated in libraries, documentation and information centers, medical premises, infirmaries and rest rooms, music rooms by a building equipment shall not exceed 33 dB(A) if the equipment operates continuously and 38 dB(A) if it operates intermittently. These levels are increased to 38 and 43 dB(A) respectively for all other reception areas

Article 5:

UNOCCUPIED FURNISHED PREMISES

AVERAGE REVERBERATION TIME (expressed in seconds)

Nursery school rest room; nursery school exercise room; nursery school playroom.

Teaching room; music room; study room; hands-on activity room; dining room and multipurpose room with volume 250 m³.

0,4 Tr 0,8 s

Medical or social premises, infirmary; sanitary facilities; administration; foyer; meeting room; library; documentation and information center.

Rooms for teaching, music, study or practical activities with a volume > 250 m³, except noisy workshops (3).

0.6 Tr 1.2 s

Catering room with a volume > 250 m³.

Tr 1.2 s

Multipurpose room with a volume > 250 m³ (1).

0.6 Tr 1.2 s and compulsory special study (2)

Other rooms and corridors accessible to students with a volume > 250 m³.

Tr 1.2 s if 250 m³ < V 512 m³ Tr 0.15 ³V s if V > 512 m³

Sports room.

Defined in the decree relating to the limitation of noise in the establishments of leisure and sports taken in application of the article L. 111-11-1 of the code of the construction and the housing.

(1) If the dining room is used as a multipurpose room, the values to be taken into account are those given for the dining room. (2) The particular study is intended to define the acoustic treatment of the room allowing to have a good intelligibility in any point of this one. (3) See article 8.

Note that the Boueni middle school site is not included in a perimeter linked to the airfield noise exposure plan. 

Article 7:

The value of the weighted standardized sound insulation DnT,A,tr, of the reception premises mentioned in article 2 with regard to the noise of land transport infrastructures is the same as that imposed on residential buildings in articles 5, 6, 7 and 8 of the aforementioned decree of 30 May 1996. It can in no case be less than 30 dB.

6.2.3.        Acoustic characteristics of the project walls

After having stated the regulatory texts, we will evaluate the characteristics of the project.

The sound reduction index of a wall provides a lot of information concerning the acoustic behaviour of a wall, especially its capacity to attenuate the sound levels emitted in an adjacent room. The calculation of its value is necessary to determine the sound insulation of a facade, which may be composed of various constructive elements (walls, windows, doors, ventilation grilles, etc.). Only the sound insulation of a facade has a regulatory character.

The first step is to identify the different building materials used to determine their respective sound reduction values.

Figure 3: Sectional view of building F

 

All the walls and their compositions are marked on the cross-section of building F and their attenuation indices have been evaluated and summarized in the following tables.

 

We recall that: the higher the loss index RA, the more the wall attenuates the noise emitted in the adjacent premises. 

Facades

Typology

Curtain wall with aluminum frame + rock wool

Total thickness of the wall

about 100 mm

Number and thickness of plates per facing

3 (sheet metal / polyethylene / sheet metal)

Weight

5,61 kg/m² (5,61 kg/m²)

Surface transmission coefficient

U = 5.6 W/m².K

Rw (C;Ctr)

-

RA

40 dB

 

Partition walls

Typology

Plasterboards screwed on a galvanized steel frame type Placostil 120/70

Total thickness of the partition

120 mm

Width of the framework

70 mm

Number and thickness of the plates by facing

2 x 13 mm

Weight

42 kg/m2

Insulation

Mineral wool (U = 0,60 W/m².K)

Rw (C;Ctr)

52 (-2;-7) dB

RA

50 dB

 

Slab

Typology

Raw concrete wall (with coating?)

Total thickness

180_ mm

Weight

432 kg/m² (2400 kg/m³)

Insulation

None

Rw (C;Ctr)

-

RA

58 dB

Ln,w

77 dB

 

Floor

Typology

COFRADAL 200 Decibel type floor with micro-perforated underside

Total thickness

200 mm

Weight

200 kg/sqm

Insulation

Mineral wool (R = 3,14 m².°C/W)

Rw (C;Ctr)

58 (-2;-8) dB

RA

56 dB

Ln,w

78 dB

Note: the values given for COFRADAL 200 correspond to the tests carried out for COFRADAL 200 Decibels with the micro-perforated underside.

Roof

Typology

Roofing sheet COVERIB ep 60/100

Total thickness

60 mm

Weight

8,6 kg/m² (8,6 kg/m²)

Insulation

Mineral wool (R = 0,50 m².K/W)

Rw (C;Ctr)

-

RA

28 dB

Note: the announced attenuation index does not take into account the presence of insulation on the underside.

6.2.4 Weighted standardized sound insulation, DnTA

Educational premises / Educational premises

 

Note: the objective is 40dB because of the presence of a communication door

The objective is well respected.

Administration room / Multi-purpose room

The objective is well respected.

 

 

Administration room / Administration room

The objective is well respected.

Note that the noisy rooms (gym, music room) are all located in the G building. There is no room next to the gym and the two music rooms.

The medical room with the social worker's office is isolated in the eastern part of building A. 

6.2.5.        Standardized impact sound pressure level, L'n,Tw

The objectives of weighted acoustic pressure levels of standardized impact noise L'nT,w measured in the various rooms are given in the table below:

Reception room

 

Objectives of the level of standardized impact noise L'nT,w [dB]

College rooms

60

Dwellings

58

 For the construction project of the Boueni secondary school, it is planned to install a COFRADAL200 type floor.

 

Normalized sound pressure level, LnAT

The equipment that will be a source of nuisance inside the premises will be

- cassette fan coil units located in the teacher's room and the meeting room

- fan coil unit located in the offices

- Square diffuser in the CDI

- Blower in the laundry/cooking room

- Extractor hood in the kitchen

- Elevators

As a result, the objectives to be respected are listed in the table below:

Reception area

 

Operation

permanent

Limited to

Operation

intermittent operation

Limited to

NR levels

 

Hall

38 dB(A)

43 dB(A)

35

Offices

38 dB(A)

43 dB(A)

35

Meeting room

38 dB(A)

43 dB(A)

35

CDI / Multipurpose room

33 dB(A)

38 dB(A)

35

Classroom

38 dB(A)

43 dB(A)

35

Medical rooms

33 dB(A)

38 dB(A)

35

All these equipments operate continuously and will not exceed 33dB(A). This is specified in the SCC of the relevant lots.  

 

Reverberation time, Tr

 

In order to calculate the reverberation times, it is necessary to determine the absorption coefficients between 125 and 4,000 Hz (frequency of the human voice) of each material developed in the interior walls of the room. These have been compiled in the following table.

Absorption coefficients

Material

alpha sabine

125 Hz

250 Hz

500 Hz

1000 Hz

2000 Hz

4000 Hz

Concrete

0,01

0,01

0,01

0,01

0,01

0,01

Gypsum

-

0,02

0,03

0,03

0,04

0,05

0,04

Closed bays

0,1

0,1

0,1

0,1

0,1

0,1

Open bays

1

1

1

1

1

1

Fibralith 50 mm

0,55 (H)

0,11

0,24

0,66

0,68

0,66

0,76

COFRADAL 200

0,85

-

-

-

-

-

-

 

As the premises are naturally ventilated all year round, it is interesting to evaluate the reverberation time when the windows are open and when they are closed. When the windows are open, they function as perfect absorbers, and when they are closed, their reflection coefficients correspond to those of a simple glazing.

REVERBERATION TIME (open windows)

Room studied

500 Hz

1000 Hz

2000 Hz

Calculated Tr60

Tr60 expected

Classroom

50 m² floor space

175 m³

Equivalent absorption area =

74,11 m²

76,86 m²

76,60 m²

Reverberation time =

0,38 s

0,36 s

0,37 s

0,37 s

0.4<Tr<0.8

 

Classroom

75,16 m²

236,06 m³

Equivalent absorption area =

74,11 m²

76,86 m²

76,60 m²

 

Reverberation time =

0,57 s

0,55 s

0,55 s

0,56 s

0.4<Tr<0.8

CDI

291 m²

1076 m³

Equivalent absorption area =

215,07 m²

187,41 m²

178,56 m²

Reverberation time =

0.80 s

0.92 s

0.96 s

0.90

0.6<Tr<1.2

Sports hall

203 m²

1218 m³

Equivalent absorption area =

205,73 m²

230,19 m²

226,07 m² 

Reverberation time =

0.95 s

0.85 s

0.86 s

0.88

0.6<Tr<1.2

REVERBERATION TIME (closed windows)

Room studied

500 Hz

1000 Hz

2000 Hz

Daylight factor : Salles de classe FLJ entre 3,3% et 5,5% - autonomie en éclairage naturel à 300 lux (DA300) supérieure à 80%

GHG emissions

• GHG in use : 47,00 KgCO₂/m²/an
Methodology used :

TEC TEC tool

• GHG before use : 823,00 KgCO₂ /m²
• Building lifetime : 50,00 année(s)

, ie xx in use years : 17.51

The calculation was made on the basis of a tool adapted to overseas departments as part of a study funded by ADEME and AQC.