The BIM approach (Building Information Modelling) is all around Architecture, Engineering and Construction professionals, but when it comes down, very few companies are founding their daily work on this paradigm and applications are really far from being homogeneous. BIM is many times (let’s say “usually”) incorrectly identified as a specific software package or a type of 3D digital model. However, BIM is much more than a newer version of CAD or a 3D visualisation tool.
The BIM approach provides a digital featuring of a building or infrastructure throughout its whole life-cycle, adding extra information to help making better and more-timely decisions upon a 3D model that allows a multidimensional analysis: 4D (evolution); 5D (costs); 6D (sustainability -including energy efficiency-); 7D (maintenance).
Although there is still a lack of knowledge on how BIM and associated digital innovations are applied across European countries, the European Directive 2014/24/EU imposes BIM Level 2 for government centrally procured projects. Level 2 refers a collaborative process of producing federated discipline specific models, consisting of 3D graphical data (those visually represented) and semantic data (those significant additions) as well as associated documentation (for instance: master plans). Information is exchanged using non-proprietary formats, such as Industry Foundation Classes (IFC).
Consequently the built heritage is subject to BIM for the purposes of documentation, conservation and dissemination, but the distinctiveness and sensitivity to meet heritage demands requires technological and methodological particularizations leading to the concept of Heritage-BIM (H-BIM). The purpose of H-BIM is to provide a 3D parametric model as a “container” of information generated all over time by different procedures, by different people, and from different sources (hw & sw). The model would capture the multidisciplinary nature of Heritage, far away from the simplicity and modularity of conventional construction, and would be very useful to study, evaluate the state of conservation and plan interventions on the assets in a profitable way. It is quite a challenge for a sector where digitization is a pending issue.
This technologically means facing many challenges, starting with the minimum amount of graphical and semantic data that would be adequate to support the activities of the sector. Two of the most important are:
The combination of 3D data with different types of images (thermography, high resolution photographs or multispectral recordings) to produce a really useful H-BIM model for exhaustive assessment.
The photorealistic texturing of 3D models for a rigorous representation of reality.
Both aspects are being worked by CARTIF to decisively help companies, managers and public administrations in the digitization of Cultural Heritage.
In two previous posts [When the Historic Buildings Talk (I) and (II) apart from making clear the importance of the conservation of the built heritage as long as describing the environmental factors that influence such conservation, we have already faced the temperature and the humidity as the two key factors to be monitored. Anyway, and in case you forgot about it, there are other aspects that also must be monitored to avoid deteriorations resulting in expensive and time consuming restorations:
Lighting (natural and artificial).
Pollutants.
In this post we are going to get involved with lighting, which mainly affects the movable goods that decorate or treasure the historic buildings. Be patient, pollutants are left for the next (and last) delivery.
Illumination can be of natural origin (coming from the sun) or artificial (coming from electrical sources), but in any case is an electromagnetic radiation that covers three ranges: infrared (IR), visible (VIS) and ultraviolet (UV). We usually call “light” the visible part to human eyes. UV radiation has a smaller wavelength than VIS and is the one with the highest associated energy. IR radiation has a longer wavelength than VIS radiation and is less energetic. Both UV and IR radiations are not necessary “to see”, but they do influence the deterioration of the materials.
When a work of art is illuminated, whether it is a painting, a polychrome, a tapestry or a parchment, the whole range of radiation (IR, VIS and UV) is absorbed by the materials of which it is composed. This radiation is associated with energy capable of altering and degrading the molecular structure of many materials, especially the most “perishable”, such as those of organic origin (textiles, pigments, leather and paper).
The UV component (highest energy), is the one with the greatest capacity to alter the materials, disintegrating and weakening, producing their yellowing. The VIS component is able to decolorize the most sensitive pigments. On the other hand, the IR component produces a heating effect that accelerates certain chemical reactions.
Thinking about this, it seems that for the assets we keep in museums, churches, hermitages, castles, palaces, archives and libraries, it would be best to preserve them in the dark. However, for study, conservation, and especially for exhibition purposes, some kind of illumination is required. Following the criteria of the IPCE, which establishes the Spanish National Preventive Conservation Plan (PNCP), these are the parameters to evaluate the risks derived from illumination:
Intensity of artificial and natural sources.
Exposure time to the illumination.
Spectrum (range) of emission of the artificial light sources, knowing if they emit in not-visible radiation bands.
Incidence of natural illumination, its orientation, and whether the radiation is direct or diffuse.
What lighting control measures exist on-site.
In turn, the assessment of the damage caused by lighting must take into account the following aspects:
Since this damage is cumulative, we should flee from high levels of illumination, but maintaining a commitment for adequate vision. By giving concrete values: 50 lux for the most sensitive materials and 150-200 lux for medium-sensitivity cultural assets.
Damage is determined by the amount of illumination, i.e. the intensity of illumination during the time an asset is exposed (lux / h). Thus, keep in mind that the damage in the case of high illumination levels with short exposures would be the same as with low levels and longer exposures.
The degradative effect of lighting also depends on other environmental factors such as humidity and air pollution.
Therefore, where we place our cultural assets, how natural light affects them, and with what kind of lamps we focus on, are critical aspects for their proper conservation (see Figure). CARTIF offers advice and tailored solutions based on a proven experience of more than 20 years in applied research to Cultural Heritage.
The importance of the train from an economic point of view is beyond dispute. It emerged as one of the most extraordinary innovations in the Industrial Revolution, because although it is true that the first steam locomotives had already been created before, it was during this period when the potential of this new means of transport could be seen.
Over the years, it has become one of the preferred means of transport for citizens, because of its safety and speed, only surpassed by the airplane. Furthermore, in contrast to the use of private vehicles, rail service contributes to fuel economy per passenger and is therefore more sustainable than other means of transport.
According to data from ADIF (Administrator of Railway Infrastructures), in Spain a train passenger consumes 5 times less litres of petrol equivalent per kilometre than traveling by car, and 20 times less than traveling by airplane. Or, for example, transporting one tonne of goods by rail consumes 4 times less litres of petrol equivalent than by road, and 1,380 times less than by air.
But, what about the construction of the railway infrastructure necessary for the movement of trains? Is it sustainable?
This was the premise of the LIFE HUELLAS project, led by CARTIF, together with the companies Vias y Construcciones and IK-Ingeniería and the University of Granada. Its objective was to improve the construction process of railway tracks in terms of their environmental impact, with special emphasis on those aspects that affect climate change.
It should be borne in mind that the railway infrastructure is made up of civil works such as bridges, viaducts, tunnels and service roads, and of the superstructure, made up of rails, sleepers, fastening material, and electrification, signalling and track safety installations. The production, construction and maintenance of all this infrastructure has a high environmental impact.
The LIFE HUELLAS consortium considered that life cycle assessment techniques, combined with intelligent data analysis, could help reduce the carbon and water footprint of railway infrastructure works by 10% and 5% respectively.
After four and a half years of intensive work, the project has managed to reduce an average of 12.9% of the carbon footprint and 14.1% of the water footprint per kilometre built in the works that have been used as pilots, i.e. better results than expected. Quite a success.
The project began with an exhaustive collection of basic information to analyse the environmental impact of the construction of railway networks, based on previously identified variables. Later, participating companies focused their efforts on studying the transformation of environmental impact into carbon and water footprints, through the development of a consolidated assessment methodology.
From this compilation, a smart tool will establish different planning alternatives applying computational intelligence techniques and showing specific values of footprint and previously selected environmental indicators. That is to say, the objective is to help in the decision-making process during the planning phase of the works.
Furthermore, the research team has developed a free online tool that provides a detailed environmental diagnosis of the processes involved in the construction of this type of infrastructure. This tool, available on the project website www.life-huellas.eu, allows the development of railway projects with not only economic, but also environmental and social criteria.
For the development of both tools, the consortium has exhaustively studied more than 460 project units and a collection of relevant sustainability variables and indicators, grouped in:
Environmental indicators: carbon and water footprint, acidification potential, photochemical oxidation and eutrophication.
Social indicators: improving working conditions, health and safety, human rights, governance, community infrastructure and job creation.
Economic indicators: project costs.
Tests were carried out during the demonstration phase of the project in two real works; on the one hand, the Ponte Ambía (Orense)-Taboadela (Orense) section of the Madrid-Galicia high speed line for the track infrastructure, that is for the earthworks (embankments, trenches, tunnels, etc.) and for the factory works (bridges, drainage, viaducts and level crossings); and on the other hand, the Antequera (Málaga)-Loja (Granada) section, for the track superstructure over which the trains run, whose main elements are ballast, sleepers, rail, electrification and signalling.
With the aim of contributing to these processes in terms of sustainability, the consortium has compiled in a guide of Good Practices the main conclusions of the experience acquired during the development of the project, as well as the different sustainable alternatives proposed.
Although LIFE HUELLAS project has already been completed, railway works on which it has been validated have effectively reduced the carbon and water footprint of their construction phase, contributing to the environmental improvement.
In addition, free access to the calculator will remain available at www.life-huellas.eu for anyone to use. You can also find us at networking and dissemination events, transferring gained knowledge, since the objective now is to promote replicability by communicating obtained results to other companies and sectors. For example, many of the railway infrastructure construction operations are common to those that build other infrastructures, such as roads, so they can also benefit from the results of the project.
Ensuring the safety of workers inside confined spaces is a critical activity in the field of construction and maintenance because of the high risk involved in working in such environments. Perhaps it would be useful, first of all, to know what is meant by confined spaces. There are two main types of confined spaces: the so-called ‘open’ ones, which are those with an opening in their upper part and of such a depth that it makes their natural ventilation difficult (vehicle lubrication pits, wells, open tanks, tanks),…) and ‘closed’ ones with access openings (storage tanks, underground transformer rooms, tunnels, sewers, service galleries, ship holds, underground manholes, transport tanks, etc.). Workers entering these confined spaces are exposed too much greater risks than in other areas of construction or maintenance and it is therefore essential to apply extreme caution.
Each confined space has specific characteristics (type of construction, length, diameter, installations, etc.) and specific associated risks, which means that they require solutions that are highly geared to their specific safety needs.
The ‘conventional’ risks specific to confined spaces are mainly oxygen suffocation, inhalation poisoning of pollutants and fires and explosions. But new ’emerging’ risks from exposure to new building materials such as nanoparticles and ultrafine particles are also emerging. In addition, as research into new materials improves, there is also a better understanding of their potential negative effects on human health and how to prevent them.
The truth is that the training of workers and current safety regulations seek to anticipate risk situations before they occur in order to avoid them and thus prevent the appearance of accidents. But several problems arise: on the one hand, the regulations are not always strictly observed (whether due to workload, carelessness, fatigue, etc.) and on the other hand, there are always inevitable risks. In the case of carelessness, systems can be proposed to minimise this type of error and in the case of risks that cannot be avoided, systems can be proposed to detect them early and plan the corresponding action protocols.
It should be noted that risk situations do not usually appear suddenly and in most cases are detectable in time to avoid personal misfortunes. There are several problems: the detection of these risks is usually done with specific measurements using the portable equipment that the workers must carry, many times the workers are not controlled to access the premises with the corresponding protection equipmente and almost never a continuous monitoring of the indoor atmosphere is done.
In recent years, new technologies and equipment have been developed that can be applied to improve security in this type of environment and reduce the associated risks.
In this type of environment, an effective risk prevention system should be based on technological solutions capable of providing answers to safety aspects throughout the entire work cycle in confined spaces: Before entering the space itself, during all work inside the enclosure and when leaving the work space (whether it is at the end of normal work or by evacuation).
The latest confined space air quality monitoring systems are based on multisensorial technology that combine different detection systems to ensure the best possible conditions to avoid or reduce the risks present in the confined spaces.
Advanced data processing techniques (machine learning, data mining, predictive algorithms) are also being applied, enabling much more efficient and rapid information extraction.
In the same way, great advances have been made in access control and personnel tracking systems, allowing us to know the position of each worker and even his or her vital signs in order to detect almost immediately any problem that may arise.
Finally, it should be noted that the use of robots and autonomous vehicles (land and air) equipped with different types of sensorization are increasingly being used to determine the conditions of a site before it is accessed. This is especially useful in those where there may have been an incident: power failure, collapse, fire,… or simply because environmental conditions are suspected to have changed and the reason is unknown.
CARTIF has been working on these issues for many years now, both in safety projects in critical construction environments (PRECOIL, SORTI) and in specific systems for tunnels and underground works (PREFEX, INFIT, SITEER).
In short, the development and implementation of new specific technologies can help to save lives in such a critical environment as confined spaces.
In two previous blogs of ‘When the Historic Buildings Talk’ (2)and(3), we have described how does affect and what is the importance of monitoring temperature and humidity as well as lighting (natural and artificial) in historic buildings. To complete this saga of pernicious aspects, the turn to the pollutants is open just now.
We all know, and suffer, that the composition of the air is altered by compounds that come mainly from the use of fuels (road traffic and heating) and industrial activities. These pollutants can trigger chemical reactions in the materials that make up the cultural assets (movable or immovable), degrading them to a greater or lesser extent. The pollutants with the highest concentration in the exterior are sulphur dioxide (SO2), oxides of nitrogen (NOX), ozone (O3) and suspended particles (PM). In addition to these pollutants that “travel free” throughout the air outside the buildings, there are others to be taken into account inside them, such as vapors of organic compounds (COV), products used in conservation and restoration tasks, and even human presence.
Again, we have to ask ourselves: what are their effects? Here it is a short description of the main ones:
SO2 is related to coal combustion and to industrial activities and transportation. It causes metal corrosion, pigment discoloration, weakening of leather and acidification of paper.
Among the NOx, the nitrogen dioxide (NO2) needs to be highlighted. It comes from combustion in vehicles and in industry, and associated effects are the discoloration of pigments and the contribution to the degradation of paper and leather.
The renowned ozone (O3) is naturally present in the stratosphere. This is a good point, because it protects us from malignant solar radiation, but at ground level is linked to road traffic and intense solar radiation. It causes the degradation of natural gums and the discoloration of pigments.
PM are characterized by their diameter, distinguishing between fine particles (PM 2.5: with diameter equal to or less than 2.5 μm), and coarse particles (PM 10: with a diameter between 2.5 μm and 10 μm –keep in mind that 1 μm is one-millionth of a meter-). The fine ones affect the discoloration and dirt of the surfaces. On the other hand, coarse ones contain highly reactive compounds (e.g. residues from incomplete combustion of road traffic). The dust enters this section: apart from its obvious aesthetic impact (denotes sloppiness and lack of care) can lead to chemical deterioration, and can serve as a habitat for insects (do you get bit?…)
In general, the study of outdoors pollution is more developed and legislated than the indoors one. However, in the field of Cultural Heritage, the study of indoor air quality is very important because of the logical conservation demands. Following once again the criteria of the IPCE, which establishes the Spanish National Preventive Conservation Plan (PNCP), these are the evaluation parameters of the risks derived from the pollution to which the historic buildings are exposed:
External parameters:
Medium where the cultural asset is located (rural, urban, industrial, coastal, etc.).
Polluting sources nearby, whether of anthropogenic origin (industrial and transport processes) or of natural origin (volcanoes, fires, sea water, animal life, vegetation, etc.).
Meteorological factors such as winds and precipitations that influence the dispersion and deposition of pollutants.
Internal parameters:
Sources of indoor pollution.
Quality of the external air and location of the asset in relation to the exterior.
Waterproofing of the building, its compartments and furniture.
Distribution of pollutants by air circulation.
Already existing air conditioning, heating and ventilation facilities, as well as their use and maintenance.
And, these are the criteria that must be taken into account for the assessment of the deterioration produced by the pollutants:
The pollution damage is cumulative, so very low limits needs to be set depending on the detection ability of available devices.
The damage is determined by the dose, i.e. the concentration of the contaminant (in μg/m3 or parts per billion -pbb-) by the exposure time. This exposure time is conveniently estimated to take into account the overall effect.
Keep in mind the mutual influence between pollution and other already known factors, such as humidity and lighting.
In conclusion, the air quality inside and / or outside the built heritage defines its conservation (see Figure). Let me remind you again that CARTIF is ready to advise you, to help you and to offer solutions tailored to your needs. You can have a look to some projects: RESCATAME, SHCITY and EQUINOX. We have been innovating in Natural and Cultural Heritage for more than 20 years. At your disposal!
In a previous post the social and economic importance of heritage conservation were already described. Also we promised that on successive posts we will go into more detail describing the three main aspects that need to be monitored to ensure such conservation. Refreshing your memory, they were:
Relative humidity and temperature.
Lighting (natural and artificial).
Contaminants.
As promised is debt, in this post we will focus on the first point (be patient, we will talk about others further on), which makes us to face the heritage “bad boys”. Relative humidity and temperature are very damaging in the effects they can cause on the materials of which historic buildings are made of. Taking advantage of Physics, relative humidity is a very useful indicator of the water content in the air (vapour), and, on the other hand, temperature indicates the level of kinetic energy (movement) of the molecules of the air.
Both parameters vary according to the local meteorological conditions, the human actions and the conservation state of the historical buildings. This means that the atmosphere surrounding the historical buildings consist of a greater or lesser amount of water vapour at a certain temperature, definitely influencing the physical & chemical stability of the materials of which they are built on, or even of which the objects inside are composed.
In this sense, it is not negligible the effect caused by people, not only by our increasingly demanding comfort requirements, but by the number of visitors. We can influence the relative humidity and the temperature in such a way that inadequate values are reached. The effects of people are added to those of the local climate (more or less wet or warm), to the assets by itself (watertightness and ventilation capacity), to the derivatives of the proximity of heat sources (heating, sunny glass surfaces, old artificial lighting systems), the proximity of cold sources (external walls or air conditioning systems), as well as sources of humidity (leaks and floods).
The main factor to be controlled because the risk of direct deterioration that could originate is just humidity. The amount of water vapour in the air results in dimensional changes such as the well-known expansion and contraction of wood, making fractures and cracks when strong fluctuations happen. In addition, extreme relative humidity values cause softening or drying of organic materials such as adhesives and binders. But it also affects the stability of inorganic materials, such as metals, accelerating the corrosion processes, especially in the presence of salts. In poorly ventilation and dirty conditions, high values of relative humidity will cause the proliferation of living organisms causing biodeterioration (from microorganisms to rodents … Disgusting!). Even health problems as shown in the image.
Conversely, the temperature accelerates the chemical reactions and favours the biological activity. It contributes to the softening of waxes and adhesives and the loss of adhesion between different materials, such as enamels.
Perhaps reading all this causes some discomfort (and even itching …). But, what can we do to prevent these adverse effects? The answer is as simple as reasonable: just avoiding too high or too low levels of temperature and relative humidity, ensuring the highest possible stability
Following the indications of the IPCE (Spanish Cultural Heritage Institute, dependent on the Ministry of Culture), which establishes the National Preventive Conservation Plan (PNCP), the evaluation of risks derived from the microclimatic factors of which we are talking about, three aspects must be monitored:
Extreme levels of relative humidity and air temperature.
The magnitude and speed of fluctuations in relative humidity and air temperature.
The proximity of sources of humidity and heating or cooling emission sources.
A wide range of sensors is available on the market to monitor temperature and humidity, either continuously or timely (see image). Indeed, it is necessary to know how to properly treat, interpret and integrate the data they provide.
What is not so frequent is using alternative methods to evaluate the effects of moisture on the materials of the built heritage. Even before these appear and the remedy is worse than the disease. CARTIF is a pioneer in the use of laser scanners to make this assessment. A recent article published in the prestigious international journal Studies in Conservation, together with the developments carried out for the European research project INCEPTION show that while 3D documenting a historical building, the level of humidity present in a known type of material could be registered in parallel. A trustworthy 2×1 to take into account in the minimum conservation expenditure times we live in. The cloister of the Cathedral of Ciudad Rodrigo (Salamanca, Spain) has been the choice for on-site validations.
An important example that gives account of the scope of applied research in cultural heritage by a technology centre within a sector where it still takes more than expected that not so new technologies to be of daily use.
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