Turkish D-ligh t : a cc e n t u a tin g h e ri t a g e valu e s wi th d ayligh t

Al-M aiya h, S a n d Elka di, HA

h t t p://dx.doi.o r g/10.1 6 8 0/je n h h.1 5.00 0 0 4

Tit l e Turkish D-ligh t : a cc e n t u a tin g h e ri t a g e value s wi th d ayligh t

Aut h or s Al-M aiya h, S a n d Elka di, HA

Typ e Article

U RL This ve r sion is available a t : h t t p://usir.s alfor d. ac.uk/id/e p rin t/39 3 2 6/

P u bl i s h e d D a t e 2 0 1 5

U SIR is a digi t al collec tion of t h e r e s e a r c h ou t p u t of t h e U nive r si ty of S alford. Whe r e copyrigh t p e r mi t s, full t ex t m a t e ri al h eld in t h e r e posi to ry is m a d e fre ely availabl e online a n d c a n b e r e a d , dow nloa d e d a n d copied for no n-co m m e rcial p riva t e s t u dy o r r e s e a r c h p u r pos e s . Ple a s e c h e ck t h e m a n u sc rip t for a ny fu r t h e r copyrig h t r e s t ric tions.

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Engineering History and Heritage

Turkish D-light: accentuating heritage valueswith daylightAl-Maiyah and Elkadi

ice | proceedings

Proceedings of the Institution of Civil EngineersEngineering History and Heritagehttp://dx.doi.org/10.1680/ehah.15.00004Paper 1500004Received 07/02/2015 Accepted 03/06/2015Keywords: developing countries/environment/rehabilitation, reclamation &renovation

ICE Publishing: All rights reserved

Turkish D-light: accentuatingheritage values with daylight

1 Sura Al-Maiyah PhD, CIBSE, SLL, ICOMOS

Senior Lecturer, Portsmouth School of Architecture, University ofPortsmouth, Portsmouth, UK

2 Hisham Elkadi PhD, FRICS, FAIB, ARIBA

Head of School, School of Built Environment, University of Salford,Salford, UK

1 2

Historic buildings have their own cultural identity, which is often related to their aesthetic qualities such as period

characteristics (geometry, size, colour, form and shape), materials and construction. Daylight is one of the primary

elements contributing to the distinctiveness of the visual environment of many historic buildings, but is rarely

considered as one of the components that shape the character of a building when adaptive preservation schemes of

historical buildings are planned. Many historic buildings were originally designed to accommodate activities different to

their new use and preserving the quality of daylight that originally contributed to their visual identity is a challenging

task. Maintaining the ‘day-lit appearance’ of a building can be particularly problematic if the building is to be used as a

museum or a gallery owing to the artefacts’ conservation requirements. This work investigated the opportunities of

maintaining the original ambient conditions of renovated historical buildings while meeting the required daylight levels

of the proposed new use. The study utilised an annual daylight simulation method and hourly weather data to preserve

daylight conditions in renovated historic buildings. The model was piloted in a Turkish bathhouse situated in Bursa,

Turkey, that is currently under renovation. The simulation model produces 4483 hourly values of daylight illuminance

for a period of a whole year using the computer program Radiance. It is concluded that daylight characteristics should

be taken into account when developing a renovation scheme. With increasing pressure on valuing historic buildings in

many parts of the world, the work reported here should be beneficial to those concerned with the conservation and

adaptive reuse of historic buildings. The study findings could also be useful to those interested in predicting potential

energy savings by combining daylighting and electric lighting in historic buildings.

1. IntroductionSeveral urban rehabilitation projects have recently been implementedin Bursa, Turkey’s fourth largest city. A number of the city’sindigenous buildings have been converted to museums, art galleries,cultural venues and community centres. Maintaining and reusinghistoric buildings – a practice well-supported by the Turkishgovernment – is often seen as a way not only to preserve the physicalbuilding fabric ‘as a tangible link with the past’ but also as anopportunity to preserve the intangible heritage of traditional skillsand craftsmanship (Cengiz, 2012). Often, the intention is to providenew accommodation for the storage and exhibition of valuableartefacts. Many historical buildings were originally designed toaccommodate different activities to their new use. Preserving thequality of daylight that originally contributed to their visual identitycan be a very challenging task. Furthermore, as most historicalbuildings were originally designed to maximise daylight, maintainingthe ‘day-lit appearance’ of a building can be problematic in terms of

artefact conservation requirements. On the other hand, successfulutilisation of daylight can create a better visitor experience andmuseum environment as well as improve the energy efficiency of abuilding. In top-lit galleries (in temperate climates), savings ininstalled lighting loads of the order of 50–60% have been estimated ifdaylight is properly integrated with artificial lighting (Carver, 1994).

Museums and art galleries are well recognised for their demandingday/lighting criteria (Kim and Chung, 2011). Museum personneloften face the challenge of illuminating the museum environmentwhile addressing the conservation requirements of museum objects(de Hoyo-Meléndeza et al., 2011). Whereas retrofitting ordinarynon-historic old buildings can offer a number of possibilities forimproving the ambient conditions and energy efficiency of buildings(Baker and Steemers, 2002), in a heritage building, a radical changeto the original quality of daylight through extensive use of artificiallight or displacement of daylight can have a critical impact on the

1

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

visual character and sense of place (Al-Maiyah and Elkadi, 2007).Although conservation practice in general is clear about theimportance of applying and adopting ‘minimal intervention’ whendeveloping a rehabilitation scheme, the practice of implementingminimal intervention is often understood by designers in terms ofpreserving the tangible aspects of a building. Indeed, preserving theoriginal tangible components of buildings such as their materials,fabric and fenestration features is key to preserving the physicalityof buildings. There are, however, many other facets of historicbuildings that contribute to their distinctive quality and significance.

Daylight is one of the intangible elements that contributes tothe distinctiveness of many historical buildings and settlements(Al-Maiyah and Elkadi, 2012). However, when initiatingpreservation schemes of historical buildings, daylight is rarelyconsidered as one of the components that shape the building’scharacter. A review of relevant documents suggests that at presentthere is no clear recognition of the role of daylight in shaping thevisual character of historical buildings. For example, in the USgovernment’s official text on preserving old buildings, Nelson(2004: p. 171) identifies the visual aspects and physical featuresthat comprise the appearance of historical buildings as follows:‘Character-defining elements include the overall shape of thebuildings, its materials, craftsmanship, decorative details, interiorspaces and features, as well as the various aspects of its site andenvironment’. Although the environment, as evident in this quote,has been identified among the various components that give abuilding its visual character, the actual description does not providean explanation of what this term means in relation to the buildingcontext, whether it is the surrounding external context or internalambient conditions. The work is mainly limited to identifyingtangible aspects related to the physical characteristics of buildings.Without a clear valuation and an understanding of the value ofdaylight in shaping the visual character of a historical building,it would be rather challenging to first establish whether daylightshould be taken into account when developing a renovation scheme,and then what might be considered ‘minimal intervention’ in termsof preserving its ambient conditions.

This paper highlights the importance of daylight in accentuating thedistinctiveness of heritage buildings. The pressure on city councilsto provide new uses for large numbers of empty heritage buildingscould result in distorted renovation projects. Appropriate analysis ofdaylight would ensure the continuing celebration of heritage incontext as well as improving energy efficiency measures.

2. Daylighting regulations and practice inTurkey

The role of daylight in improving the energy efficiency in buildingshas recently received much attention in energy performanceregulations in Turkey. The value of daylight and the importance ofmaximising its effectiveness for illuminating building interiors,which were clearly stated in building performance legislationsintroduced in 2008, have been further emphasised recently with thelatest introduction of the new Turkish lighting standard.

2

As a candidate country for European Union membership, Turkeyadopted the European standard for lighting in work places(EN 12464-1:2011) (BSI, 2011) in January 2012 as the Turkishlighting standard (TS EN 12464-1:2011). Item 4.10 of thisstandard emphasises the role of daylight provision in buildings andprovides, in clause 5.4, lighting requirements for retail premisessuch as restaurants and hotels, theatres and concert halls, as well asexhibition halls and museums. These requirements can also guidethe reuse of historical buildings. However, while recommendedlight levels for most of these public premises are given in theEuropean guidelines, there are no values given for museums, wherelighting requirements are mainly determined by the displayclassification. However, other reliable international guidelines suchas those recommended by the Illuminating Engineering Society ofNorth America (IESNA) or the Charted Institution of BuildingServices Engineers (CIBSE) can be used (and have often been usedin previous similar studies) to establish lighting requirements in amuseum or gallery environment.

As well as the Turkish-adopted European standard, there are currentlytwo other pieces of legislation in Turkey that include guidelines onbuilding lighting – legislation for the effective use of energy sourcesand energy consumption and legislation of energy performance inbuildings, both dating back to 2008 (Erkin et al., 2009). However,neither provides recommendations for lighting levels or illuminancevalues. With the new lighting standard now in place, there is aneven better ground or base to measure how traditional buildingsperform against recent requirements. As the renovation and reuse ofold buildings is a well-received practice and is increasingly emergingin many other major cities in Turkey, the work reported here shouldbe beneficial for those concerned with conservation practice and thereuse of historical buildings in the region.

3. Daylighting requirements in museumbuildings

While the presence of natural light with its vibrant qualities isan attractive design feature in many building types, in a day-litmuseum environment, certain preventive measures have to betaken to minimise its ‘deleterious’ effects on museum collections.Daylight has the most desirable colour-rendering qualities foraesthetic reasons, which are important to a museum’s function.However, the high energy in the ultraviolet region of the spectrumcan cause chemical and physical damage to fragile objects incollections such as discolouration, fading, yellowing and surfacecracking. Unnecessary visual light can also pose a threat to certaintypes of museum objects. The ‘reciprocity law’ states that thecumulative photochemical effect ‘is directly proportional to theillumination levels multiplied by the time of exposure’ (US DoI,1999). Thus, an exposure of 200 lx for 6 months can cause as muchdamage as 100 lx exposure over 1 year. Reducing exposure time istherefore another important measure to limit damage from light. Onthe other hand, the rate and extent of deterioration brought about bythe amount of light and exposure time varies between the differenttypes of objects depending on their material properties and chemicalcomposition.

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

In general, museum artefacts can be grouped into three categoriesbased on sensitivity to light – highly sensitive objects derivedfrom organic origins, partially sensitive objects containing organicand inorganic substances, and insensitive objects having geologicalorigin. IESNA established illuminance recommendations andannual exposure times for the various material-type categoriesfound in a museum collection (Rea, 2000). As illustrated in Table 1,a maximum of 50 lx is recommend for highly sensitive objects and200 lx and 300 lx for partially sensitive and insensitive objects,respectively. Similar illuminance values are also given in the CIBSElighting guide (CIBSE, 1994). In terms of exposure time, the valuesgiven in the IESNA guidelines are lower than those given in theCIBSE lighting guide (Table 1); the latter values are based on theassumption that the lights will be either extinguished or maintainedat a very low level outside museum opening hours. While reducingthe length of exposure to light is important in terms of conservationconsiderations, determining the correct level of illuminance indisplay spaces is equally important in terms of comfort andvisibility. The limits recommended in Table 1 are widely acceptedas practical for reducing damage while maintaining adequateviewing conditions (CIBSE, 1994) and were thus adopted in thepresent study for assessing annual illuminance values and totalannual exposure to daylight in the selected case study.

4. MethodologySeveral site visits to selected heritage buildings (buildings recentlyconverted to museums or to be converted to museums) in Bursa wereconducted in May and August 2012 and September 2013 (Figure 1).The selected buildings included Demirçi bathhouse (a small bathhousecurrently under renovation), UluumayMuseum (an old religious schoolthat became a museum in 2000) and Ordekli bathhouse (converted toan art and cultural centre in 2008). The Muradiye Madrasa (an oldschool) is also soon to be converted into a museum. The planned useof Demirçi bathhouse is a cultural centre where art exhibitions will be

held regularly to benefit the village community. The building thereforeoffers an opportunity to test the possible use of its original ambientdaylight conditions for a better adaptive reuse strategy.

Until recently, daylight studies of buildings have mainly focusedon assessing the illuminance values received into a building orpart of a building on selected seasonal dates and times of day.Key seasonal dates that are often used for performing such analysesare the winter and summer solstices and the fall and springequinoxes. Since the early 2000s, an increasing number of authorshave argued the limitation of such an approach and advocated amore realistic systematic approach of evaluation, preferably hourlyannual evaluation (de Hoyo-Meléndeza et al., 2011; Mardaljevic,2000, 2006; Mardaljevic et al., 2011).

The revised methodology using annual evaluation of daylightilluminance levels is essential in daylight studies of museums andexhibition buildings given the sensitivity of artworks and otherobjects to excessive exposure to illuminance levels. Since naturalilluminance values are mainly affected (among other things) bysky conditions and the thickness of the sky cover, it is importantto separate the various sky conditions and choose the right skytype for each step/hour of the evaluation. For this reason, Bursasky conditions were classified into three types using hourly cloudcover data obtained from a standard weather file for the city (AshraeIWEC weather file for Bursa) – clear sky (less than 30% cloudcover), partly cloudy sky (cloud cover of 30–70%) and overcast(more than 70% cloud cover). This classification of sky types is inline with the CIE definitions of standard general sky models and useof this hourly statistical based approach (Kensek and Yong Suk,2011; Lighting Design and Simulation Knowledgebase, 2015) issimilar to previous work reported by Tzempelikos and Athienitis(2005). Hourly daylight simulations for a period of 1 year wereperformed to calculate annual illuminance values received into the

Maximum illuminance: lx

Maximum annual cumulativeexposure: lx h

CIBSE

IESNA CIBSE IESNA

Objects insensitive to light (e.g. metal, stone,glass, ceramics and most minerals)

Subject to heating andadaptation effects

Depends on exhibitionsituation; max 300 lx

—

Depends onexhibition situation

Objects moderately sensitive to light (e.g. textileswith stable dyes, oil and tempera paintings, ivoryand wood)

200

200 600 000 480 000

Objects highly sensitive to light (e.g. textiles,costumes, tapestries, prints and drawings,silk and writing inks)

50

50 150 000 50 000

Table 1. Maximum illuminance levels and accumulative exposurevalues given in the IESNA lighting handbook (Rea, 2000) and theCIBSE lighting guide (CIBSE, 1994) for various types of exhibits

3

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

selected bathhouse using existing CIE models for clear, overcastand intermediate sky conditions in the Integrated EnvironmentalSolutions (IES) Virtual Environment Radiance.

Bursa is located in north-western Anatolia within the Marmararegion between 40°11¢N latitude and 29°03¢ E longitude. The cityhas a Mediterranean climate with dry hot summers and an averageof 14 h of daylight and mild winters with an average of 9 h ofdaylight. However, classification of the sky conditions using thecloud cover data mentioned earlier reveals a total of 1945 h ofclear sky conditions in Bursa, 1362 h of mixed sky conditionsand 1322 h of overcast conditions during daylight hours per year.An illustration of the average annual direct normal illuminancereceived by the city in units of lux hours (lx h) according to theweather file used in the study is shown in Figure 2. As illustrated inthe figure, the amount of direct normal illuminance received by thecity from the solar disc over the summer period (June to September)can be as high as 39 000 lx h. Thus, rehabilitation projects (in theregion) that seek to recycle historical buildings to re-function asmuseums should take advantage of the availability of such high

4

levels of illuminance while controlling its contribution to the overallvisual environment of the buildings.

Radiance is well known as a powerful and highly accurate modellingtool. Several previous studies with similar content to this workhave used Radiance to assess daylight levels and visual comfortcriteria in reused historical buildings. Al-Sallal and Dalmouk (2011),for example, used Radiance in an evaluation of the daylightingperformance of one of the traditional residential buildings in theUnited Arab Emirates that was converted to a museum. Daylightlevels and ambient conditions in the present town hall in Florence(Palazzo Vecchio), where some of the most precious and ancienttapestries are exhibited, were also examined using the Radiancemodelling tool (Balocco and Frangioni, 2010). A three-dimensionaldigital model of the bathhouse was therefore developed using thegeometry model creator (Model IT) in the IES Virtual Environmentand the daylight simulation package Radiance was used to performthe annual illuminance evaluation. Reflectance values used forthe internal walls and the ceiling (including the domes) were 50%and 70%, respectively; a reflectance of 20% was used for the

(a)

(d) (e) (f)

(b) (c)

Figure 1. Demirçi bathhouse with internal views of the hammamshowing the top-lit dome of the studied northern hot room ((a)-(c)),Uluumay Museum (d) and Muradiye Madrasa ((e) and (f))

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

floor. These figures were established based on a description ofthe original surface finishes identified in the restoration report thatwas submitted by the team for planning permission.

In many building types (e.g. office buildings and schools), daylightstudies are usually performed by calculating the horizontalilluminance values on the work plane where most of the visual taskstake place. By contrast, in exhibition halls, where some artworkcan only be mounted on the walls either vertically or horizontally,evaluating the distribution of daylight on the vertical surfaces of aroom is as important as evaluating the values of work planeilluminance. For this reason, an internal view with a fixed cameraposition that shows the various zones illuminated with daylightwithin a selected room in the bathhouse was chosen for the

evaluation (Figure 3). A series of reference points assembled on fivemain axes on the south-, north- and west-facing walls of the roomwas then used to predict the hourly values and the total exposure toilluminance during daylight hours (5 a.m. to 7 p.m. in summer and8 a.m. to 4 p.m. in winter). The points were situated on sections ofwalls likely to be used for exhibiting artworks at three differentheights: 0·70 m (point c), 1·45 m (point b) and 2·2 m (point a) abovethe floor. The simulation model produced 4483 illuminance valuesfor every calculation point.

5. Case study building: Demirçi bathhouseThe plan of Demirçi bathhouse (or hammam) follows the traditionallayout of Roman baths, with a cold room, a semi-hot room and a hotarea (Figure 4). The cold room, known as the frigidarium, is usually

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18 783 5889 11132 19982 17823 11808 1451368 3671 2189 11

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Hou

r

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Figure 2. Annual direct normal illuminance received in Bursa in unitsof lux hours

Illuminance: lx95085075065055045035025015050

S11 1

W2 3

N

a

b

c

(a) (b)

Figure 3. (a) Location of the digital sensors used in the analysis.The sensors were placed where objects are likely to be mountedat different heights: 0·70m (point c), 1·45m (point b) and 2·2m(point a) above the floor. (b) Work plane illuminance

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

used as a transitional space between the changing rooms and theheated area. The semi-hot room or tepidarium is the room wherebeauty treatments such as oiling and massaging of the body takeplace, while actual bathing takes place in the hot room (caldarium),often considered the most important place in a bath building.Traditionally, a bathhouse was both a ‘complex structure and anexpensive enterprise’ that was carefully designed and perforated tomaintain certain ambient conditions necessary for the bathingrequirements taking place (Salam-Liebich, 1983: p. 193). Hence,like in many other hammams, there are no windows in Demirçihammam to avoid drafts and save and control steam and heat.Daylight is provided through small glass openings studding thedomes, allowing a minimum amount to filter through (Figure 1).Only the hot area of Demirçi hammam survives today; the othertwo areas (the cold and semi-warm) were destroyed and rebuiltlater. These additions, which were demolished and rebuilt, will bere-functioned along with the original hot complex as a culturalcentre, as mentioned previously. The dimensions of the caldariumare 7·21 m × 8·7 m, including two hot rooms, a small cell for privatebathing and the furnace room (Figure 4).

6. Results and analysisThe transformation of heritage buildings for new uses challengesthe possible maintenance of their original characteristics. Daylightis clearly a key ingredient of such transformations, particularlywhen the new use includes exhibitions of artefacts. Demirçihammam provides an excellent case study to carefully assess thepossible use of daylight not only to illuminate artefacts sensitivelybut also to maintain the identity and ambience of a wonderfulheritage building.

Year-round hourly measurements provided an accuraterepresentation of daylight performance in the building. The domeof the hammam provides interesting temporal daylight distributionthroughout the year. The interesting setting allows for testing thediverse daylight patterns on the north-, south- and west-facingwalls. The distribution of dome-lit daylight differs greatlythroughout the year (Figure 5) but provides steady levels of daylighton the surrounding walls.

6

Analysis of daylight levels on the three walls shows thepossibility of maintaining acceptable levels of daylight withinthe safety levels (480 000 lx h) for moderately sensitive exhibitssuch as oil paintings, frescos, ivory and wood. A further in-depthinvestigation revealed particular times at particular points onthe walls when precautions need to be taken. While the overallcumulative illuminance falls within the accepted range, contactwith illuminance that exceeds maximum exposure levels(200 lx) at any particular time could cause serious damage toexhibits.

All points on the south wall appear to receive acceptable levelsof illuminance exposure all year around. The average monthlyilluminance remains under 140 lx (Figure 6). Similarly, theaccumulative levels similarly fall well within the 480 000 lx h limitall year around (Figure 7). As shown in Table 2, the accumulativeilluminance values received by the upper section of the wall,the centre section and its lower area range between ≈456 000 lx hand ≈350 000 lx h.

The north-facing wall receives a maximum monthly averageilluminance of 220 lx in its upper part (1a) during April (Figure 8).The upper part of the wall seems to be the only section that wouldrequire attention during April and August if sensitive objects are tobe exhibited. Similar results were also obtained for the accumulativeilluminance. The presence of direct normal illuminance at thisparticular point and time of the year can be as high as 80 000 lx,resulting in accumulative values well above the safety limitsrecommended for moderately sensitive objects. Precautions aretherefore to be taken to avoid exhibits placed on the upper andmiddle sections of the wall during August (Table 2). Showcasesequipped with ultraviolet protective coatings can add another levelof safety in spots where there might be a concern about the level ofdaylight.

The west-facing wall is a long running wall that would provide aconvenient surface for the exhibition of artefacts. For testingpurposes, this wall was therefore divided into three parts (left-hand,centre and right-hand sections). Analysis of the left-hand side of

A

N

(a) (b)

Figure 4. (a) Plan of the hammam showing the heated area in themiddle and the cold and warm areas on the west side on thebuilding; the cross-section line A indicates the position of the

camera used in the simulation. (b) Digital model of the historicsection of the hammam

7

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

lx1901701501301109070503010

14 Jan 14 Feb

14 March 14 April

14 May 14 June

14 July 14 August

14 September 14 October

14 November 14 December

Figure 5. Interior views of the studied northern hot room showingthe seasonal variation in daylight levels at 10.00 a.m. on a specificday (the 14th of every month) throughout the year. The scale bar

on the left-hand side of each false-colour rendering was fixedbetween 0 and 200 lx in order to illustrate the difference inilluminance values

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

the west-facing wall shows no reason for concern (Figure 9). Themaximum monthly average was again mostly under 120 lx exceptfor a slight increase during April in the upper part of the wall wherethe average value predicted was 135 lx (Figure 10). The annualaccumulative exposures were also under the 480 000 lx h limit,allowing for unconstrained usage of the wall for the exhibitionof moderately sensitive materials (Table 2). Similarly, the centrepart of the west-facing wall shows higher illuminance levelsduring the summer period, particularly 25 May to 25 June, on theupper part of this section (Figure 11). The right-hand side of thewest-facing wall however has much higher levels of illuminance forthe middle part of the wall for a longer period of the year (May toAugust).

On a monthly basis, the central section of the three selected wallsof the room (point b, located at 1·45 m height) seems to receive

8

an average illuminance of 60–90 lx between September andFebruary and about 110–130 lx between March and August.These figures fall well within the 50–200 lx comfort criteriarange set by CIBSE and IESNA stated earlier. However, if theupper limit of the range is to be met, the maximum intensity ofadditional lighting needed to compensate for the lack in daylightis 140 lx in winter (December to January) and about 70–110 lx forthe rest of the year. This additional lighting could be provided aspart of the design of display containers and should thus be carefullyadjusted depending on the season in order to prevent dramaticchanges to the ambiance of the space. As much as blocking accessto daylight can affect the visual perception of a room (as notedduring a site visit to Uluumay Museum where daylight openingswere fully blocked and replaced by artificial lighting), addingunnecessary artificial lighting can similarly alter the ambientconditions of a place and thus its visual perception. Carefullyintegrating daylight and artificial lighting can thus not only assist inpreserving art objects and maintaining the original lightingconditions of a heritage building but can also contribute to improveits energy efficiency. A reduction in the use of artificial electriclighting would provide savings in energy bills. The current practiceof entirely blocking daylight in order to protect museum artefactsnot only modifies the ambience of heritage buildings but alsoincreases energy costs.

7. ConclusionsDaylight is a key ingredient in maintaining the identity of culturalbuilt heritage. In Bursa, interventions to adapt historical buildings tomore contemporary use are essential for their sustainability. Suchinterventions, however, cannot just rely on the new Turkish lightingstandards, particularly where museums are intended as the newfunctions for these buildings.

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Figure 6. Average monthly illuminance on the three sections of thesouthern wall

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Figure 7. Daily total illuminance on the southern wall between1 January and 31 December

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5690

5Jun

5026

644

166

3831

349

780

3987

933

634

10483

148

454

3894

048

202

4750

542

716

5578

948

781

4339

3Jul

4872

741

531

3584

247

148

3744

431

676

6386

645

665

3594

846

558

7056

537

377

5411

245

531

3896

1Aug

4864

443

150

3723

645

857

3787

632

229

6122

946

053

3652

358

555

7196

539

289

8002

070

192

3893

4Sep

3725

131

571

2721

835

083

2823

823

475

4656

833

351

2581

852

901

3286

824

578

6161

035

995

2871

1Oct

3209

727

023

2272

030

199

2397

819

728

3875

927

588

2144

331

634

2557

220

380

3705

929

046

2354

1Nov

2656

522

313

1883

324

549

1966

916

154

3125

522

616

1752

324

434

2035

716

535

2915

523

142

1920

4Dec

2200

718

410

1545

320

417

1333

913

339

2585

118

678

1455

320

137

1368

313

683

2378

719

128

1581

4To

tal

45624

540

245

134

467

144

498

235

398

029

855

764

005

442

252

233

328

448

832

648

611

433

635

559

039

647

390

737

335

0

Table

2.Ann

ualtotal

illum

inan

ceat

differen

tlocatio

nson

thethreeexam

ined

walls

9

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

10

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

The current study shows that a thorough evaluation of seasonalvariations in daylight and hence careful distribution of artefacts in aheritage building not only maintains its ambience and character butalso assists in protecting exhibited objects from damage due toexcessive exposure to daylight. The outcomes of the simulation ofDemirçi hammam highlight the importance of yearly daylightmeasurements rather than analysis on the basis of data from sampledates. The particular structure of this building, together withdaylight access through the dome structure, necessitates accurateinvestigation of the dynamic profile of daylight across various wallsurfaces. The results also clearly show the possibility of usingdaylight across many walls of the building to exhibit sensitiveobjects and artefacts. The results can be used to maintain theambience and original experience of the building despite the strictlight requirements of its intended new use.

0

50

100

150

200

250

300

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Illum

inan

ce: l

x

West 2aWest 2bWest 2c

Figure 11. Average monthly illuminance on central section of thewestern wall

0

20

40

60

80

100

120

140

160

180

200

1 Ja

n7

Jan

14 J

an28

Jan

7 Fe

b14

Feb

21 F

eb28

Feb

7 M

ar14

Mar

21 M

ar28

Mar

7 A

pr14

Apr

21 A

pr28

Apr

7 M

ay14

May

21 M

ay28

May

7 Ju

n14

Jun

21 J

un28

Jun

7 Ju

l14

Jul

21 J

ul28

Jul

7 A

ug14

Aug

21 A

ug28

Aug

7 Se

p14

Sep

21 S

ep28

Sep

7 O

ct14

Oct

21 O

ct28

Oct

7 N

ov14

Nov

21 N

ov28

Nov

7 D

ec14

Dec

21 D

ec28

Dec

Illum

inan

ce: l

x

West 1aWest 1bWest 1c

Figure 9. Average daily illuminance on the left-hand side of thewestern wall (reference points 1a, 1b and 1c) between 1 Januaryand 31 December

0

20

40

60

80

100

120

140

160

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Illum

inan

ce: l

x

West 1aWest 1bWest 1c

Figure 10. Average monthly illuminance on three sections of theleft-hand side of the western wall

0

50

100

150

200

250

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Illum

inan

ce: l

x

North 1aNorth 1bNorth 1c

Figure 8. Average monthly illuminance on three sections of thenorthern wall

Engineering History and Heritage Turkish D-light: accentuating heritagevalues with daylightAl-Maiyah and Elkadi

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