Architectural Solutions

Shadometal

Introduction

COMFORT & SOLAR HEAT GAIN

We can all appreciate the benefits ofworking in an environment where thetemperature is comfortable. For officebuildings in the summer, the optimumtemperature is 24°C, with a range of +/- 4°C.

However, this temperature range can soonbe exceeded during the hotter months, dueto the effect of solar radiation throughglazing. Temperatures as high as 35°C to40°C have been recorded.

This can result in an uncomfortably warmenvironment which can adversely affectthe productivity and concentration levelsof the occupants inside. In air conditionedbuildings uncontrolled solar heat gain canincrease cooling loads, plant size andoverall running costs.

In addition, independent studies haveshown that productivity increases whenpeople sit near a window, enjoying thebenefits of natural daylight. A lack ofdaylight can result in an over-use ofartificial lighting, contributing to internalheat gain.

Architects and Consultants areincreasingly recognising the part that solarshading systems can play in bothenhancing the quality of the internalenvironment, and saving energy.

Solar shading systems can be designed tomaximise natural daylight whilstcontrolling solar heat gain and glare.

Approved Document L2 of the BuildingRegulations requires avoidance of solaroverheating. Please see page 4 for moredetails.

SHADOMETAL

Colt offer two external solar shadingsystems within the Shadometal range:

Solar C is a fixed solar shading system asBrise Soleil that may be installed eitherhorizontally or vertically onto the buildingfaçade or roof.

Solarfin, is a system of fixed orcontrollable fins offering greater designflexibility. When linked to a sun trackingcontroller, Solarfin can offer the mosteffective degree of solar control withoutcompromising light levels on dull days.

Louvres are also available in othermaterials such as glass, wood, terracottaclay and translucent acrylics.

COLT’S TRACK RECORD

Colt has more than 40 years experience in designing solar shading solutions.

With operating companies locatedworldwide, Colt has a broad productportfolio to meet your needs.

Colt was the first to incorporate electricitygenerating photovoltaic cells into solarshading louvres.

Colt understands that a low energybuilding fails on its weakest link, so it canprovide integrated solutions that covermany aspects of design includingdaylighting and natural ventilationsolutions.

Colt is dedicated to innovation and has a comprehensive design capability,including prototyping and testingfacilities. We would welcome theopportunity to develop solutions to matchyour unique requirements.

2

Front Page: Zurich Airport photographed by Ralph Bensberg

Controllable perforated Colt Shadometal louvres were specified by Nicholas Grimshaw and Partners which cover the complete Westfacade of the A500 Airside Center. The control system adjusts the position of the louvres in response to changing climatic conditionsand available daylight.

SUN PATH DIAGRAM

This illustration shows the azimuth and altitude ofthe sun for a latitude of 51.7o North

“The challenge is to maximise daylight entry intothe internal space whilst minimising

solar heat gain.”

South North

West

East

SE

NW

NE

SW

Solar Altitude for21st June

Solar Altitude for21st Sept

Solar Altitude for21st Dec

Latitude 51.7o NThe sun rises in the East and sets in the West.Thesun travels in an arc, reaching its highest altitude inthe South (in the Northern hemisphere)

Latitude 51.7o N

360o10o

20o

30o

40o

50o

60o

70o

80o

90o

100o

110o

120o

130o

140o

150o

160o

170o180o190o

200o

210o

220o

230o

240o

250o

260o

270o

280o

290o

300o

310o

320o

330o

340o350o

20:00

18:00

16:00

14:00

12:00

10:00

08:00

06:00

04:00

18:00

16:00

14:00

12:00

12:00

10:00

08:00

06:00

10:0014:00

June

March andSeptember

December

10o20o

30o

40o

50o

60o

70o

80o

3

1m

2.9m

17m

9m 4m

7m

Stairs

Stairs andServices

ControllableSolar Shading Fins

Building Regulations

The Building Regulations (England andWales) require that “reasonable provisionshall be made for the conservation of fueland power in buildings”. Within this isincluded a requirement to limit exposure tosolar overheating (2002) or excessive solargains (2006).

This can be an onerous requirement for ahighly glazed façade intended to maximisenatural daylight entry.

Approved Document L2 provides guidanceas to how compliance can be achieved. The guidance changes when the 2006 edition comes into force in April 2006.

A simple approach to compliance is to show that the heat gains to a defined floorarea do not exceed a set average over theperiod between 07.30 and 17.30 in the month of July.

Until April 2006 the set average gain is asolar gain of 25 W/m2. A calculation method is provided in Appendix H toApproved Document L2, 2002 edition.

From April 2006 the set average gain is atotal gain of 35 W/m2. The total gainincludes the solar gain and casual gains dueto people, lights and equipment. No specificcalculation method is given, but therecommended data precludes direct use ofthe previous Appendix H calculation method.

Note: for spaces served by comfort coolingsystems, meeting the TER (target CO2

Emission Rate) is sufficient for compliancewith Regulation L1 but limiting the totalgain makes it easier to meet the TER.

4

Waters Edge Visitor Centre, Barton-on-Humber.Fixed Solarfin louvres fitted to flitch plates to

curtain walling.

55m

7m

Glazing

N

NW

SESW

NE

6 m perimeter floor area

WORKED EXAMPLE

The following example explains the use ofsolar shading for compliance with clause1.23 a) of Approved Document L2 (2002)and clause 60 a of draft ApprovedDocument L2A (2006). The calculationpresented is from Appendix H (2002) butthe general principles apply whicheverdocument is used.

Take a typical modern fully glazed officeblock as shown, with heat absorbingdouble glazing and internal blinds toprevent glare. Assume that the floor is open plan except for the enclosed staircores, which are disregarded. Then:

PPPPeeeerrrriiiimmmmeeeetttteeeerrrr fffflllloooooooorrrr aaaarrrreeeeaaaa::::

A = 642m2

GGGGllllaaaazzzzeeeedddd aaaarrrreeeeaaaa ((((SSSSWWWW++++SSSSEEEE))))::::

A = 182.7m2 q = 198 W/m2

GGGGllllaaaazzzzeeeedddd aaaarrrreeeeaaaa ((((NNNNWWWW++++NNNNEEEE))))::::

A = 188.5m2 q = 160 W/m2

UUUUssssiiiinnnngggg tttthhhheeee eeeeqqqquuuuaaaattttiiiioooonnnn HHHH1111 ((((ssssoooollllaaaarrrr llllooooaaaadddd ppppeeeerrrr

fffflllloooooooorrrr aaaarrrreeeeaaaa))))::::

Q =

1 (182.7 x 198 + 188.5 x 160) x 0.66 x (1- 0.1)

This solar gain significantly exceeds theacceptable limit of 25 W/m2 (2002) or (35 – casual gain) W/m2 (2006).

There are two basic options available todecrease the solar gain. Reduce the glazingarea or provide improved solar protection.9

62

slw

slw

p

g 1 s 1

g 2 s 2

c

(*)

(*)

(*) (*)

Reducing the glazing area would mean thatglazing would be limited to a single striponly 1.2m high on each floor.1

IIIImmmmpppprrrroooovvvviiiinnnngggg tttthhhheeee ssssoooollllaaaarrrr pppprrrrooootttteeeeccccttttiiiioooonnnn ttttoooo aaaacccchhhhiiiieeeevvvveeee

22225555WWWW////mmmm2222 rrrreeeeqqqquuuuiiiirrrreeeessss aaaannnn iiiimmmmpppprrrroooovvvveeeedddd ccccoooorrrrrrrreeeeccccttttiiiioooonnnn

ffffaaaaccccttttoooorrrr ooooffff::::

f = 0.66 x 25 = 0.27

Using equation H3 of Approved Document L2to calculate the shading coefficient of a systemto meet f = 0.27 gives:

Therefore shading coefficient must be lessthan 0.19.

This can be achieved using the existingglazing and blinds with the addition of anexternal automatically controlled movableColt Solarfin system. Due to theeffectiveness of the Solarfin system it maybe possible to offset some of the additionalcost by reducing the glass specification.

642

Q = 62 W/m2

c

SC = 0.27 x 0.7 = 0.19

Castlepoint Shopping Centre, Bournemouth.Solarfin louvres set onto prefabricated

faceted structure.

5

(*) Standard Data fromAppendix H

Solar C - Fixed Solar Shading

An important part of the design process isto consider when it is beneficial to protectglazing from the sun. If glare is controlledby other means, such as internal blinds, itcan be useful to allow winter sun into thebuilding to supplement heating andincrease light levels. Solar C Brise Soleilis ideal for this, since it can be configuredto provide the required protection.

A simple horizontal Brise Soleil (such asSolar C) is best suited to façades facingbetween South East and South West, butwith careful design Solar C can beeffective on most façade orientations.

Natural light entry and ‘vision out’ mustplay an important part in the overalldesign process.

Consideration needs to be given to theamount of natural light entering thebuilding, as well as the need to have aclear view to the outside.

Sunfax is a program that evaluates theeffectiveness of alternative solar shadingdesigns, and which permits the selectionof the most effective design.

The Solar C system is a fixed louvresystem that can be designed to meet theneeds of any building.

Patented louvre clip enables the louvre blades tobe adjustable in increments of 15o

Unlike conventional ‘Z’ section shapedblades, which may reduce both direct anddiffused light, the Solar C blade isdesigned to be effective at controllingsolar heat gain whilst allowing through afair proportion of diffused light betweenthe louvre blades.

Six blade profiles are available varying inwidths from 100mm to 150mm.

A perforated blade is also available with awidth of 110mm.

The pitch between the blades is normallyset at 100 mm but this can be varied tosuit the blade size and angle.

Solar C is normally installed incontinuous lengths to fixed raftersprojecting from the building. This willprovide uniform light entry to thebuilding.

If a panellised system is preferred, thenthis is available with profiled end plateswhich can make a prominent feature to abuilding.

8 am (5 pm)9 am (4 pm)

10 am (3 pm)

11 am (2 pm)

12 pm (1 pm)

8 am (5 pm)9 am (4 pm)

10 am (3 pm)11 am (2 pm)

12 pm (1 pm)

8 am (5 pm)

9 am (4 pm)

10 am (3 pm)

11 am (2 pm)

12 pm (1 pm)

Summer

Spring/Autumn

Winter

Vertical shadow angle(the projected angle of the solar altitude)

Porsche & Volvo Offices, Munich, GermanySouth facing(Northern Hemisphere)

6

7

Solar C - Assembly

14

3

1

2

Type C100Max Span 1.65m

Type C100pMax Span 1.55m

Type C110Max Span 1.70m

Type C140Max Span 1.80m

Type C150Max Span 1.85m

Type C150gMax Span 2.00m

Type FP180rAttached toLouvre Clip

Type FP180Attached to Rafter

Type FP 90 NAttached to Rafter

LOUVRE PROFILES

FRONT FASCIA PANELS

Type TR 15/30Fixing to

Steelwork

Type TR 23/30Floating

Intermediate

Type TR 45/30Cantilevered

Type TR50/30

Type TR 90/30

BracingStrut20/20

RAFTERS

1.Aluminium Rafter2.Adjustable Clip3. Fascia Profile4. Louvre Blade

8

Fixed to curtain walling with bracing strut

Support bracket fixedthrough cladding to a separate structure

Optimum angle

SUPPORT CLIP

Both a fixed and an adjustable clip areavailable. The adjustable clip allowscomplete flexibility of louvre and rafterangle, since the louvre angle can bechanged on site.

The patented louvre clip is adjustable in increments of 15o. The action of attaching the louvre blade to the rafterfixes the angle.

Fixed angle clips are also available in 30,45, 60 and 135o. Clips are available ineither grey or translucent.

The plastic clip allows for thermalexpansion of the blade and ensures thatlouvre blades cannot rattle against therafters.

SUPPORT RAFTERS

Five basic rafter designs are available.Their selection depends on the fixingmethod and the loadings on the structure.

For any projections less than 1m, therafter can be cantilevered from thebuilding structure, assuming the windloadis not excessive.

Maintenance walkways with kick platesand hand rails can be attached to the rafterto enable access for cleaning.

INSTALLATION

Ideally installation should be carried outby Colt trained installers. If the louvresare installed in continuous lengths, thelouvres are packaged up in break downform for on-site assembly.

An adjustment in the louvre system canaccommodate building tolerances of up to10mm.

Particular attention should be paid tosuitable fixing locations and the structuralintegrity of the structure into which thelouvre is attached. This should beconsidered at the early stages of theproject.

Truckstop, Dunstable.Bespoke vertical fins and Solar C.

9

Solar C - Specification

10

Product description:

Fixed external solar shading system, for installation at (select) angle.

Louvre blades are attached to extruded aluminium box section rafters, with(select) variable/fixed macrolon clips in(select) translucent/grey.

The system is attached to the buildingstructure with extruded aluminium bracingstruts and stainless steel brackets.

Material:

Louvre blades, support brackets andmullions are manufactured from extrudedaluminium alloy A1MgSi 0.5. Fixings arefrom stainless steel.

Blade pitch and angle:

(select) mm @ (select) degrees.

Louvre projection:

(select) Horizontal mm / Inclined / Vertical /Horizontal & Vertical / Inclined & Vertical.

Finish:

(select) Mill aluminium / Polyester powderto RAL / Anodised.

Manufacturer:

Colt International LtdNew Lane HavantHampshire PO9 2LYTelephone 023 9245 1111Fax 023 9245 4220

Product reference:

Solar C type (select from)

C100, C100p, C110, C140, C150, C150g

(If applicable) Facia panel type (selectfrom)

FP 180, FP 180r, FP 90N

Marlborough House, Leatherhead.Solar C louvre installed onto Colt glazed pyramidswith integrated Colt Firelight ventilators.

Ionica, Cambridge.A solar shading system comprising aluminiumsupport arms with circular front tubes which wereinfilled with Solar C blades welded to the arms andsupplied as fully assembled modules.

Trinity and All Saints College, Leeds.Panellised horizontal Solarfin

connected to end plates and fixed backto the curtain walling.

Clissold Leisure Centre, London.Vertical Solar C covers the glazing, which can bepivoted at an angle to facilitate easy cleaning of theglass behind.

11

Solarfin - Fixed and Controllable Solar Shading

12

Benenden Hospital, Kent.The Architects John McAslan & Partners specifiedColt Solarfin for the façade.

Colt Universal Louvre was also installed forscreening and ventilation.

Left.The fins have virtually no impact on the viewto the exterior.

13

1 pm

2 pm

3 pm

4 pm

5 pm

6 pm

7 pm

8 pm

1 pm

2 pm

3 pm

4 pm

5 pm

6 pm

1 pm

2 pm

3 pm

4 pm

Solarfin - Introduction

On façades from South East to SouthWest, a Solarfin system that is installed infront of the glazing will provide superiorperformance to a Brise Soleil system,whilst optimising daylight entry and theview to the exterior.

On more Easterly or Westerly façades,any fixed system will be a compromisedue to the fact that the low summer sunangles need to be controlled.

A controllable Solarfin system is ideal forsuch façades.

WinterSpring

Summer

Although aesthetic considerations play animportant part in the design of a building,functionality is critical, both for comfortand energy saving and to meet the legalrequirements imposed by ApprovedDocument L2 of the Building Regulations.

When controllable fins, are fitted verticallyin front of a window, as shown below,these may be designed to offer the mosteffective degree of solar control withoutcompromising light levels on dull days.

West facing utilisingSolarfin ControllableSolar Shading

14

Controllable fins reduce the likelihood of‘overshading’ or ‘undershading’ that canhappen with fixed solar shading. As shownbelow, they can be moved to the optimumshading angle depending on the time ofday. On dull or overcast days the louvreswill automatically open to maximisedaylight entry.

On dull days, light sensors send signals tothe control system to fully open the fins toallow the occupants maximum naturaldaylight and vision to the outside at alltimes.

Controllable solar shading is also effectivewhen fitted to glazed rooflights.

Too much shading,too little light entryinto the building

Optimum shading

Too little shading,light passesthrough thelouvre blades

John Lewis, Cambridge.Solarfin fitted both to the customer

entrance canopy and in front of the facade.

Benenden Hospital, Kent

Bristol Myers Squibb, Liverpool.

Clear Channel Outdoor, London.Both fixed and movable vertical

Solarfin louvres installed onto the facade.

15

Solarfin

Health and Safety Executive, Bootle.Colt both the supplied the horizontal Solarfin and the

supporting steelwork. Colt also provided natural andsmoke ventilation, fire curtains, rooflights and weather

and screening on this project.

16

Solarfin louvres may be fixed at any angleand can rotate under motorised control.Spans can be up to 6m withoutintermediate support and up to 10m withintermediate bracing rods. Fabricated andperforated fins are also available.

All principal components aremanufactured from extruded aluminiumalloy type 6063 T6 with stainless steelfixings. Controllable fins can pivotthrough 120 degrees and can be controlledby astronomical data operating theactuators to track the path of the sun.

SUNFAX

Sunfax is a specially designed computerprogram that evaluates the effectiveness ofa solar shading system. With this programColt can assess a system design andprovide a bespoke solution to meet allaspects of a project.

Backed by an experienced technicalsupport team, Colt can work with thecustomer from the earliest stages of theproject to design an aesthetically pleasing,high performance solar shading system.

Tate Britain, London.Controllable Solarfin fins installed on top of Colt Azur rooflight systems.

COLT SOLARFIN

Colt Solarfin is a fixed or controllableexternal solar shading system that may beinstalled either vertically or horizontally infront of the façade.

It may be combined with other Coltproducts such as rooflights and glazedfaçades.

A Solarfin shading system can reduce solarheat gain, lower air conditioning runningcosts, and lessen glare whilst maximisingthe use of natural daylight.

With over 20 standard profiles, fins areavailable as one-piece extrusions in widthsup to 400mm and as multiple clippedtogether extrusions in widths up to1050mm.

Arup Fitzrovia, London.Fixed Solarfin supported

by drop rods, andUniversal Louvre fitted

to plant rooms.

17

STANDARD RANGE

CEL 60/20

CEL 150/34

CEL 250/40

CEL 300/50

CEL 400/60

CEL 480/80

CEL 120/20

CEL 200/34

CHL 250/40

CEL 350/55

CEL 400/80

NNNNOOOOTTTT TTTTOOOOSSSSCCCCAAAALLLLEEEE

Perforated

Solarfin Standard Profiles

Perforated 250/50

18

Special profiles available on request

Solarfin Specification

Product description:

(select) Controllable / Fixed external solar shading system, designed to reduce solarglare and solar heat gain.

Extruded aluminium fin profiles aredesigned to prevent or reduce directradiation through windows in summer,while keeping visibility through windowsas clear as possible.

Material:

Fins and rafters are manufactured fromextruded aluminium alloy 6063 T6.Fixings are from stainless steel.

Fin pitch and angle:

(select) mm @ (select) degrees. (Select angle for a fixed system only).

Finish:

(select) Mill aluminium / Polyesterpowder to RAL / Anodised.

Stainless steel components to be self-finished if applicable.

Manufacturer:

Colt International LtdNew Lane HavantHampshire PO9 2LYTelephone 023 9245 1111Fax 023 9245 4220

Product reference:

Colt Solarfin type (select from standard range)

CEL 150/34, CEL 200/34, CEL 250/40, CEL 300/50, CEL 350/55, CEL 400/60 and CHL 250/40,

or telephone Colt to discuss your specialrequirements.

Paradise St Car Park, LiverpoolFixed Solarfin with special ladder mullion systemand mitred corners.

19

Bespoke Profiles

UTZ Offices, Berlin, Germany.Bespoke vertical solar shading fins that can bemanually altered to control internal daylight levels.

Aldersgate, London.Curved horizontal screening fins and panelised louvre panels.

Asda, Poole.Fixed Solarfin fitted to vertical steel supports.

Addenbrookes Hospital, Cambridge.Perforated cladding and perforated

Solarfin for screening and ventilation.

Colt realise the importance of creativityand individuality when designing abuilding and offer many bespoke solarsystems in such materials as perforatedaluminium, wood, terracotta clay, andtranslucent acrylics.

20

SD Worx, Germany.Controllable perforated Shadometal.

Crosby Leisure Centre, Liverpool.Stucco embossed aluminium louvres set onto

prefabricated faceted structure.

Natural History Museum, London.Between the Colt glass façade and walkway of the stunning South façade is a bespoke, controllable fin,which is half perforated to provide additional daylight when in the closed position

21

Control Systems

TOTAL CONTROL

Although fixed solar shading performswell on a South facing façade,performance is dramatically reduced on aEast or West facing façade which receivesa large amount of sunshine during the day.

A controllable shading system can bestovercomethis problem. Sun trackinglouvres follow the path of the sun, makingsure the solar shading system alwaysoptimises the amountof daylight entry.

On dull or overcast days the louvres arecontrolled in such a way that if cloudspass over the building, the louvres willautomatically open to maximise daylightentry and then later revert back to theiroriginal position.

The Sun path diagram (right) for latitude52

oN shows the position of the sun

throughout the day during the months ofJune, March/September and December.

PIA (HIDDEN ACTUATOR) SYSTEM

The innovative PIA system is a mullionintegrated drive system which is availablefor all movable systems.

Large exposed actuators are no longerrequired since the PIA system providescentral pivoted control within the mullions.

Usually drive mechanisms for solarshading system are visible. The PIAcontrol system allows the controlmechanisms to be housed of sight withinthe mullions. In addition to this aestheticfeature, each control mechanism withinthe mullion can drive the louvres from0°to 360°. This enables greater flexibilityof application for light reflection orcleaning for example.

Unobtrusive, compact façades can becreated which are equally suited forboth vertical and horizontal applications,with almost silent running operation whenthe louvres are moving. Installation is verysimple since all components are suppliedfully pre-assembled. Also, the mechanicalintegrity of the system is assured: sincethe louvres are individually fixed into theirbearings, the likelihood of structuralfailure is very much reduced.

The control mechanism is discreetlycontained within the mullion instead ofhanging externally.

CONVENTIONAL ACTUATION PIA SYSTEM

22

Ilford recorder, Ilford.A series of movable Solarfin louvres were integrated

into a “PIA” mullion-integrated actuation systemconsisting of box section mullions with hidden

mechanisms inside, controlled by a Colt ICS 4-Linkcontrol system.

Colt Solar Shading systems may be controlled in three different ways:

� Hand control via lever or crank handle.� Electrically operated via actuators, which require a controller such as ICS 4-Link, SolTronic or a client BMS.� Self powered via a thermal hydraulic controller Colt Girasol. This operates autonomously and requires no additional source of

power other than the sun.

GIRASOL

Girasol operates solar shading louvreswithout the need for electrical power or asophisticated control system.

Absorber tubes, enclosed by mirrors,force a hydraulic cylinder to open or closethe louvres according to the position ofthe sun.

SOLTRONIC

SolTronic is ideally suited for small tomedium sized projects.

It is a simplified version of ICS 4-Linkand can control up to ten actuators in anysingle zone.

It responds to external weather conditionsautomatically calculating the position ofthe sun, and adjusts the position of thelouvres accordingly.

ICS 4-LINK

ICS 4-Link is ideally suited to largerprojects with more complex controlrequirements.

It is a generic control system that canoperate HVAC, smoke control and solarshading systems.

It has a wide variety of operating modes,including sun tracking, daylightingoptimisation and PV illumination. Itresponds to timers and sensors to ensurethat the building ‘reacts’ appropriately tothe sun’s position and to the weather.

Remote operation is available via aninternal modem interface and a manualoverride is also possible.

Tubes are filled with a special hydraulic fluid andas the sun moves over the building, there will bean imbalance of heat between the two tubes andthe louvres will open or close as appropriate.

Actuator

Girasol System

Solar Shading System

AAAA

23

This control system may run on any conventional PC.

Subj

ect t

o m

odif

icat

ion.

Pub

licat

ion

num

ber

PD 1

1: 1

2/06

“Col

t” a

nd th

e C

olt l

ogo

are

regi

ster

ed tr

adem

arks

of

Col

t Int

erna

tiona

lL

icen

sing

Lim

ited.

©C

olt I

nter

natio

nal L

icen

sing

Lim

ited

2006

.

COLT SERVICE

Part of the Colt Group of companies, ColtService offers a comprehensive range of maintenance packages incorporating the maintenance and repair of all building services equipment including non Colt products.

Colt Service provide a 24 hour, 365 day emergency cover as standard.

MAINTENANCE & TESTING

Colt solar shading systems requirevirtually no maintenance.

All components of any system should be serviced at least once a year and tested monthly.

COMMISSIONING

Proper commissioning of movable SolarShading Systems by experts is essential.We recommend that our specialist staffcommission and certify the system.

Colt International LimitedNew Lane HavantHampshire PO9 2LYTel +44(0)23 9245 1111Fax +44(0)23 9245 4220info@coltgroup.comwww.coltgroup.com

Architectural Solutions

Climate Control

Smoke Control

Service and Maintenance

“People feel better in Colt conditions”

Co

lt

I n t e r n a t i on

al

19

3 1 - 2 0

06