The possibilities of switchable glasses in the new «daylight norms»

The Halio daylight system as part of the EN 17037

Already in 1935, the DIN 5034 gave validity to a German body of norms, which

included interior lighting with daylight. This makes it all the more astonishing that

the norm is only followed more than 80 years later, by a norm valid throughout

Europe the EN 17037 «Daylight in Buildings». On the basis of the latest scientific

findings, it provides recommendations for indoor daylighting and it is also dedi-

cated to the topics of views, tanning and glare protection. Thanks to their intelligent

control options Halio glass makes an important contribution to these important

aspects of modern daylight planning.

The functionalization of Daylight

Around 100 years ago, light came into the focus of architecture for a variety of

reasons. Modernist architecture challenged the cramped living conditions in the

backyards of the cities under the motto «Light, Air and Sun for All» and deve-

loped solutions for affordable and healthy living. Light and daylight were above all

dimensions of home hygiene. The health aspect of light was limited to the biologi-

cal effects of non-visible areas of sunlight such as infrared and ultraviolet light. It

was known that ultraviolet light killed bacteria, and sunbathing eased skin diseases,

vitamin D deficiency and rickets.

The daylighted factory created better working conditions but served primarily to

increase productivity in the early days of «Fordism». The 24-hour factory was born.

Humans, hens, plants and other living things just had to be put in the right light to

become more productive. Today’s light researchers have a different opinion.

At the turn of the millennium, a receptor in the eye

that carries the light-sensitive molecule melanopsin,

responds to the visible region of light and directly

influences our circadian rhythm, our internal clock, and

keeps bodily functions such as the immune system and

metabolism in motion.

We know that light influences us in many ways,

depending on criteria such as the time and the pe-

riod of the light exposure, the horizontal and vertical

illuminance and the light spectrum. As you know,

the high blue light content in the morning lowers the

release of the sleep hormone melatonin and stimulates

the release of serotonin when we wake up. Cold white

light in the evening delays the production of melatonin,

therefore we fall asleep with difficulty. The more time

we spend indoors, the more we isolate ourselves from

our natural internal schedule. Today it is known that an

adjustment of this clock increases the risk of certain

diseases.

Non-visual effects as a basis for daylight planning

Most properties of natural light can be reproduced with

artificial light. But why do we usually perceive the intensi-

ty and changes of daylight as much more pleasant? Why

does it have such a great influence on our moods and

helps us to perceive and classify our surroundings holis-

tically? Current researchers agree that the mechanisms

of action of light are so complex that we have still a long

way to make from standards specifications to dynamic

lighting conception in buildings. But there are directions

recognizable.

For example, in their publication “Human Centric Light-

ing (HCL): provisional appraisal in June 2019, Canazei

and others add the recommendation to include as much

daylight as possible, to supplement cold-white artificial

light. By putting a vertical proportion as high as possib-

le during the day and, in the evening, to reduce vertical

sections of the light and to use punctual light. Daylight

raises the tolerance of higher light intensities for the user,

who perceives visual discomfort significantly later, day-

light is rated higher in quality of light than any artificial

light source and, moreover, daylight is the most efficient

light source for generating increased vertical brightness,

the authors further state.

The higher is the amount of daylight, the greater is

the challenge of finding the balance between dayligh-

ting, tanning and heat input. «The daylighting market

has been tremendously creative in recent years,» says

Robert Jagger, Country Sales Manager DACH at

Halio International, a Belgian manufacturer of swit-

chable glass systems.

«Dimmable glazing automatically reacts to the weather

outside and can be programmed as needed. Intelligently

networked, Halio glasses create ideal conditions in

terms of visual quality, thermal comfort and energy

efficiency,» continues Robert Jagger.

Switchable glasses in the flashpoint between light, comfort and energy efficiency

Especially for these three criteria, EN 17037 gives designers and builders the possibility to jointly set target values for indoor daylighting. The norm

distinguishes between the levels «Low», «Medium» and «High». It introduces the concept of daylighting, which for the first time evaluates daylight quality

over a whole year and incorporates local weather data into the calculation. The individual stages are fulfilled when 50% of the area has reached the

respective target illuminance during 50% of the daylight hours and when at least 95% of the area reaches the minimum target illuminance during 50%

of the daylight hours.

Recommendations for the daylight supply through daylight openings in vertical and inclined surfaces

EN 17037 gives target values for daylight quality

Recommended level for vertical and inclined daylight openings

Target illuminanceET

Space’s proportion for the target valueFplane, %

Minimum target illuminanceETM

Space’s proportion for the minimum target valueFplane, %

Share of daylight hoursFtime, %

Low 300 lx 50% 100 lx 95% 50%

Medium 500 lx 50% 300 lx 95% 50%

High 750 lx 50% 500 lx 95% 50%

Daylight openings in façades according to EN 17037

Also, for the view from the room, the tanning and the glare protection three recommendations levels from «Low» over «Medium» to «High» were determined.

What is new is that the outward view of the location of the users in the room is used and is included in the evaluation, whether the sky and the ground are visible.

When the sun is shining, the duration of the sun’s rays (minimum recommendations of 1.5 h to 4 h) is calculated on a specific key date while exceeding a minimum,

geographically different sun altitude angle. The reference points are in the window level. Last but not least, EN 17037 recommends the value of Daylight Glare

Probability (DGP) as the value for glare protection, i.e. the probability that a person will be blinded by light. Key figures such as vertical illuminance at the eye,

luminance, as well as geometric angle and position of the glare source are included in the DGP simulation.

Only «low-transmission glazing» or «electrochromic

glazing», which allow only a very low light transmission

in the dimmed state, are recommended in addition to

conventional shading systems as a suitable glare and sun

protection.

Even if the minimum requirements for daylighting in

EN 17037 have been set very low - even on a bleak winter’s

day outdoor illuminations of 3000 lx will still affect our

eyes - it is an expression of the fact that daylight planning

is still becoming increasingly important.

Uncolored Halio glasses have a transmittance of 65%, with a color rende-

ring index of 97% in the clear state, they are completely neutral in color and

show no unnatural bluish cast or grid or erratic gradients even with increasing

gray tint. In less than three minutes Halio glasses can be dimmed to a mini-

mum transmittance of 2%, the Halio glass system is by far the fastest on the

market today. Depending on the glass structure, Halio glasses achieve

Ug values of up to 0.6 W / (m2K). «Halio’s controlled system automatically

optimizes the amount of daylight and can therefore save up to 22% on

the costs of air conditioning and heating,» explains marketing director Ka-

tia Hansen. Halio is therefore recommended for all sustainable construction

projects, no matter if it has to respect Passive House, Minergie, BREEAM

or LEED norms.

Halio dynamic glass is the future of the facade. A modern facade automati-

cally regulates, incorporating a dynamic sunscreen, providing perfect thermal

insulation and natural ventilation, all in a slimline design. The precise flowing

tint of Halio glass makes the facade smarter and more efficient. Thanks to

Halio, Smart Buildings become even smarter.

Light management is sun protection plus comfort plus energy efficiency

The high degree of automation is ensured by the Halio Cloud. It communicates with all common building

automation systems and can be addressed either via apps, voice assistants or decentralized control panels.

«The Halio Cloud is well equipped for the application of EN 17037,» adds Hansen. We can incorporate individual

preferences as well as geographic location, orientation of facades and weather conditions into our daylight

management. «

Contact:

Halio International

Katia Hansen

Marketing & Communication

Halio Europa & Middle East

Avenue Jean Monnet 4

1348 Louvain-la-Neuve, Belgium

Tel. : +32 486 89 35 16

Email : katia.hansen@halioglass.com

www.halioglass.com

Ansprechpartner:

Press Relation:

Interview International

Ingrid Hecht

15, rue Martin Luther

67000 Straßburg, Frankreich

Tel.: +33 (0)3 88 15 55 88

E-Mail: info@interview-international.fr

About Halio International

Halio is the exclusive supplier of Halio products and services to

the building industry. The joint venture between AGC, the world’s

largest flat glass manufacturer and Kinestral Technologies, Inc.,

developer and manufacturer of the Halio smart–tinting techno-

logies, consists of the two business entities: Halio North America

and Halio International. This partnership leverages the partners’

respective strengths and expertise: AGC’s reputation and

100+ years of experience in glass technologies and Kinestral’s

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