Post 281 ⇒   by Gautam Shah  →


In Commerce, Industry and Government many different types of specifications are used for acquisition of products or assignments. The process depends on nature of relationship between the acquirer, or assigner on one side and the vendor, supplier, assembler or manufacturer on the other side. It depends on the traditions in the field. Format of specification is formed by the technology and quality of available public specifications used for the product or process.


These are restrictive kind of specification limiting the bidding to equivalent products of a given one or few brands. The brands chosen are presumed to be the best, adequate or representative one in the market. It is killing the competition. The supplier of unspecified brand is required to show that offered product is indeed equivalent. To supply goods of the named brand, various dealers of the same product will have to contest, a condition unlikely to be allowed by the main distributor. Such a restricted practice is employed by Government Departments and organizations who do not wish to spend time or effort to define-search for product specifications. The procuring agency automatically gets the right to determine equivalence. This process has doubtful legitimacy, but is none the less practised.


Lists of qualified products are mainly formed by Government agencies as recommendation to their departments for purchase of commonly used items. In some countries Non governmental organizations (NGOs) set up filters to identify undesirable products and processes. Such lists often suggest uses and typical price range for such items. The criteria for formulating and updating a QPL are in a public domain, and periodically updated. A purchase mentions the code and calls for + or – over the standard price tag is usually in public domains.

In India, The Central Purchase Organization DGS&D (Directorate General of Supplies & Disposals) typically creates lists goods with approved rates. The term goods used in this manual apply generally to all articles, material, commodities, livestock, furniture, fixtures, raw material, spares, instruments, machinery, equipment, industrial plant etc. purchased or otherwise acquired for the use of Government but excluding books, publications, periodicals, etc. for a library.



Design specifications mention dimensional and other physical requirements of the item. Design here means a method or scheme of creating or putting together an item. It is the most traditional kind of specification. Design specifications are prescription of what an entity should be in its completed form. These are also called Item Specifications, as the design details are itemised in terms of the execution, material’s technology or mode of execution. Design specifications show how the item must be created, and often with the additional information (but, usually less effectively) what the final product is intended to be (goal, dreams, perception). Here the problems arise, because a manufacturer or supplier is emphatically told what and how to produce or deliver. In most cases this means a demand for a very customised Item. It leaves no chance for the manufacturer or supplier to offer, technologically or economically superior item, or one from their own standard range.

Indian Space Programme Design specification assembly


Performance specifications list the expectations how an entity should function or what it must deliver. Here the user communicates the requirements as to What will be an acceptable product, and How the adequacy of the product will be judged. The performance specification is more related to how a product performs or functions and at what cost, and less related to its dimensions, materials or configuration. The vendor gets substantial freedom in offering the most appropriate technology. For such specifications it is mandatory to explain in detail the results required and how these be will be checked. All performance requirements must be matched with tests for adequacy. There is a tendency to demand performance requirements that are very high in comparison to actual projections, which leads to cost escalation.

Problems arise when test methods for judging adequacy of a product could require a ‘Destructive Testing’ or a ‘Laboratory or Plant-based facility’. Full activation or critical testing of an atomic reactor may not be feasible, or a long term performance of material cannot be checked in any setup. The provision of assurance by the supplier becomes very important.

Performance requirements


Operational specifications have lesser bearing on how an item is created or procured, but relate to the working of a system. These relate to the functioning of the item, and for that reason product formation, delivery, installation processes must have built in strategy for operation or conduction with optimum efficiency. Operational specifications are not performance specifications, but details about mitigating risks arising out of operation of a system.



Post 280 – by Gautam Shah



Windows served two main functions for interior spaces: Ventilation and Illumination. To this was added the view out with the advent of glass. The window became part of shop front and it served the purpose of view in.


For several centuries a window was a minor entity for Illumination of domestic interiors. The door provided enough day time illumination. Domestic finer activities, such as the needle craft were conducted just inside or outside the threshold of the door. In deeper spaces, such as inner rooms, roof holes provided basic illuminance. In early public buildings, illumination was provided through smaller openings covered with parchment or alabaster. The areas of window opening though small, was distributed over a larger surface made available through increased interior heights.

Door as the only opening in the dwelling

In a tropical house admission of light is usually accompanied by heat gain, but the breeze coming through a door balances the interior environment. In tropical climates interiors tend to be darker to reduce the heat gain compared to colder climates where greater illumination is perceived as warmth. Naturally illuminated lit spaces are perceived to be healthier.


Ventilation in extreme climates such as very warm and cold, occurs through the temperature gradient between outside and inside. In hot and humid climates, the temperature gradient is not acute enough to cause natural air movement of a sufficient quantum. The need for large volume air movement is significant for moisture control in hot humid areas.


Ventilation requirements of an interior space vary depending on the number of occupants, nature of indoor cooking activities, fuels used for indoor heating and cooking, duality of distinct entry and exit points, the structure of the dwelling and scope for micro passive ventilation. To a smaller extent the ventilation needs are governed by the siting of the dwelling, such as the densely populated urban colony. Ventilation also depends on the nature of opening (cracks, crevices, holes), size of opening, number, distribution, location, orientation, and external climatic conditions (snow, rain, windy).

Micro ventilation

Cracks and gaps being unintentional are usually insufficient for heavier needs of ventilation and cooling or heating of spaces such as for toilets, kitchens, production areas and public spaces. Planned openings like windows on external face provide for such needs at the location, elevation, depth and in required quantity (such as a rate of air change -dilution, and the rate of air flow). The effectiveness of windows in achieving desired ventilation depends also on which windows are opened, how far they open, and the nature of shutter fixing.


Ventilation requirements for a dwelling are regulated by the cooking activity. In hot arid climates cooking is done outside the house, in an attached facility or semi open lean-to shades. Kitchen areas are sited in isolated spaces or corners. Cooking with a centric hearth occurred where it also contributed heat for warming. Moisture dilution is an important factor of ventilation requirements. In hot humid climates water utilities like storage and usage (bathing and washing) are placed in the Chowk like interior courtyards, outside or away from the dwelling. According to cannons of Building design, the Vastu Shastra, place of water is in the North-East side. This orientation provides for exposure to south-west face, the warmest or Sun side in the Northern hemisphere.

Punjab India -Open air – outdoor cooking minimises internal ventilation needs

Ventilation is required to dilute the odours, moisture, carbon dioxide, airborne pollutants such as dust, smoke, volatile organic compounds (VOCs), latent heat from air, objects, etc. and encourage evaporation of body moisture and thereby cause cooling.

Windows provide ventilation, more effectively in rooms with internal doors (that is a door not opening to an exterior face), and especially when the exterior face door is closed for security reasons, such as at night. Movement of air between indoor spaces, and not the outside, is called transfer-air. Transfer-air has very little role in diluting the polluted air.


Windows placed on opposite sides and on same axis are better ventilating devices. The position of window vis a vis the work plane or task is determined whether one wants a draught-breeze over the body and the task, or avoid it. The nature of shutter opening also determines the direction of the internal air movement.


Windows with shutters opening outward often obstruct the wind path, but double hung sash windows and sliding shutters which open within the frame are better as receptors. Casement window shutters with offset hinges or friction stay which create a small gap on the jamb side help in catching the breeze. Hoppers, awning and jalousie windows direct the breeze due to the angle of opening. The depth of a window and its surround also affects the nature of ventilation. Splayed sides create funnel effect to catch the breeze.

Mumbai Houses -One face for ventilation

Most building codes suggest minimum opening area (including doors, windows, etc.) @4 to 5% of the floor area. But actual ventilation requirements are higher such as during rainy days, moisture content is very high, or when during celebrations and social events lot of people gather in a room. Nominally openings (including doors) @20% of the floor area, are sufficient for the purpose of ventilation, provided some sections of the openings are located within the human height (1.75 mts). Even in unoccupied rooms some ventilation is required to remove fumes and moisture generated by materials, plants and condensation. Minimum volumetric requirements for ventilation are 23 to 25 CMt per person per hour, and 12 to 16 CMt per Kg of fuel burnt. Large sized openings create turbulent air movements, whereas cracks and crevices create a viscous or laminar flow.


Commonly ventilation is measured in terms of entire interior volume of air gets replaced per hour, it is called air changes per hour, ACH, but requirements for air for well being per person are also specified. Minimum 0.35 ACH, but the supplied air must be no less than 15 cfm/person or 7.5 l/s/person. Since 2003, the standards for ventilation have been changed on floor area basis which is from 3 CFM/100 sq. ft. or 15 l/s/100 sq. m. to the 7.5 CFM/person or 3.5 L/s/person. To find the total amount of outside air required, one needs to add 3 cfm/100 sq. ft. or 15 l/s/100 sq. m. to the 7.5 cfm/person or 3.5 l/s/person. Thus, the air change rate requirement will vary by the size of the house and the occupancy.

Ventilation is required for a fire emergency from areas like corridors, stairs, etc. Openings for ventilation are necessary for all climate conditions, but control requirements are very acute in warm and extremely cold climates, due to outward leakage of internal air.


For adequate ventilation the building must take full advantage of prevailing breezes on the site. This includes consideration of: seasonal and diurnal wind patterns, land contours and other topographical features, shape and form of the building, height of the openings, axial position of the openings, work or task plane, physical state and age of the occupants, etc. Other important conditions are position of the window, the form of the surrounds and projections and design of the window shutter.



Post 279 – by Gautam Shah



Organizations exploit both, the individual talents and traits of their employees. FIRST, persons with only required qualities are sought. SECOND, better compensations are offered for hiring specific qualities. THIRD, incentives are offered to individuals who show readiness to reformat their talents and traits. FOURTH, employees unable to convert are punished, or shifted out of the organization. Employees of the organization are motivated in different ways to modify or upgrade their expertise.


Beyond paying out incentives, organizations use Job assignment as the key method, to exploit the human resources. Organizations divide their projects, assignments etc. into manageable lots or jobs of various skill and resources-based specialities. These are then assigned to individuals or teams as distinct roles. Jobs are presented as an opportunity, challenge, and incentive to a person or a team.


Design creation processes have many stages such as project formulation, concept evolution, planning, detailing, job award processes, execution, client and consultant relationships. In very small offices few individuals take on many of these roles. In very large offices there could be several individuals or departments to handle these functions.

design process

A leader of the organization or project manager diverts a job from one to another person, to achieve diverse results. Jobs are assigned to remove the tedium of repetitions, or to provide new training or exposures. Jobs are also given out, to infuse new thoughts, work methods, and utilize different resources (plant, equipments, tools, talents). An organization becomes innovative and creative through such shifting of the personnel.

In design organizations personnel are identified in terms of their talent, and experience. In medium to large organizations common pools of human and other resources are formed. Project managers draw from such pools their requirements of human and other resources.

An organization is formed of employees of different talents and personality traits. These manifest in their attitude and conduct. A person may reflect multiple characteristics within a situation, or show a different personality if adequately motivated and conditioned.


Dream-weavers are prolific generators of ideas and new concepts, but lack the skill to detail them. The dream-weavers are mercurial and often have a fear of failure. A dream weaver must be an extrovert otherwise never gets acknowledged.

Technocrats have a talent of visualizing structured entities. For them an entity is conceivable, if it is structured and so practicable. Technocrats are fastidious, uncompromising, and hard-headed. A technocrat may get entwined in detailing the parts, and may lose the grasp of the holistic scheme.

Exponents enjoy advocating ideas or schemes, without bothering either its authorship or practicability. They feel that the public attention received through the advocacy is the measure of their skill and success.

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Patrons are not necessarily resourceful people, but are ready to support any new activity that takes them away from their routine chores, provides a novel experience, and keeps them busy. A person may become a sponsor by virtue of the position and powers to allocate resources. Such people are motivated by strategic gains through various sponsorships.

Arrangers are expert manipulators, and keenly look for a chance to jump into any difficult situation to manage it. As a risk taker they collect a lot of benefits, and very fast.

Orthodox are very over careful by personality. Their conservatism is due to a struggle less life or due to old age lethargy. They detest change, but if instrumental of causing even minor innovation, take a great pride.



Post 278 – by Gautam Shah



Gypsum mineral is found as layered sedimentary deposits in association with halite, anhydrite, sulphur, calcite and dolomite. It is a very common sulphate mineral found in all regions of the world, and is of great commercial importance.

Gypsum formation Capo Bianco

In well-developed crystals the mineral is selenite. The fibrous massive variety, called a satin spar is translucent and opalescent, and is used in jewellery. The fine-grained rock like variety is called alabaster, which is carved and polished for statuary and decorative items. Gypsite is the earthy and powdery variety.

Selenite crystal

Gypsum is in use by man, in the form of plastering and cementing (binding) material and in the form of alabaster for beads and other decorative items, for more than 12000 years.

The word Gypsum derives from the Greek, gyps =burned or baked (calcined) mineral, or the Greek word gypsos =chalk or plaster. Gypsum as a rock-material was known in Old English as spear stone due to its crystalline projections. Selenite was used in Greek, alluding to the pearly lustre (moon light) on cleavage fragments.

Plaster was discovered in Catal-Huyuk in Asia in an underground fresco, and in Israel Gypsum floor screeds were found from 7000 B.C. During the time of the Pharaohs, Gypsum was used as mortar in the construction of the Cheops Pyramid (3000 B.C.). In the Middle Ages and the Renaissance, decorations and artistic creations were made of plaster.


Modern uses of Gypsum include, as sulphur donating additive in fertilizers, filler in paper and textiles, and setting time retarder in Portland cement. Substantial part of Gypsum in calcined form is used as plaster of Paris, Keene’s cement, board products, and ceiling tiles and blocks.

Common Gypsum is composed of Hydrated Calcium Sulphate (CaSO4 ·2H2O). Gypsum plaster is a white cementing material made by partial or complete dehydration of the mineral gypsum, sometimes with additional setting time retarding or hardening agents. Applied in a plastic state (with water), it sets and hardens by chemical recombination of the gypsum with water.


Plaster of Paris is a hemi-hydrate of calcium sulphate, composition CaSo4, ½ H2O made by calcining the mineral gypsum, at temperatures 120°–180° C (248°–356° F), creating a composition of CaSo4, 2H2O. The hemi hydrate calcium sulphate, in commercial forms contain many impurities, which govern the chemical behaviour. The powdered hemi-hydrate is mixed with water to form a paste or slurry, the calcining reaction is reversed and a solid mass of interlocking gypsum crystals with moderate strength is formed. The mixing of water with plaster causes an exothermic chemical reaction that releases heat. This heat helps to harden the Plaster of Paris, allowing it to set. Upon setting there is a slight contraction. This dimensional consistency makes it suitable for casts and its release. Different types of Plaster of Paris are available for different applications that have varying setting time, required quantity of mixing water, and hardness on drying. These characteristics are controlled by the calcination, additives, impurities, granular size-distribution, amount and ambient temperature conditions.


Mask making from Plaster of Paris

Rapid setting qualities may set even before complete hydration has taken place and so may not leave any time for tempering and rendering. Insufficiently hydrated mass attracts moisture later on, resulting in expansion, warping and peel off. Such failures can occur in low setting qualities, when for any reason the amount of hydration water and mixing efforts are insufficient. Particle size distribution is an important factor governing the behaviour of the Plaster of Paris. Too many fine particles quicken the setting without allowing full hydration of the mass. Sand and mineral lime particles improve the wettability of the initial mass and workability during casting or rendering. Hydraulic Lime on getting carbonated can increase the surface hardness at a later date.


It is called Plaster of Paris because Paris became a centre for production of plaster material during the 1700s. It was than mainly used for coating masonry surfaces, as it set at a much faster rate than Lime plaster. It was also used to cover wooden surfaces to make them fire resistant. Plaster of Paris releases water vapour when exposed to a flame, making it ideal as a fire resistant material.

Dental cast

Plaster of Paris is used to make ceiling boards and ornamental cornices. It is also used for making casts and moulds for sculptures, forensic investigations, dentistry, jewellery and for immobilizing broken bones. Gypsum plasters are now used as leveler coating before painting, micro cracks and crevices filler.

Large surfaces of Plaster of Paris require some inter-mass reinforcing and substrate keying. Jute, cotton, threads, coir, hair, viscose, fibreglass, are some of the commonly used fibres for reinforcement. Masonry surfaces of bricks, rough stones and cement plasters offer sufficient substrate bonding. Wood, Metal and Polished stone surfaces require substrate keying through wood, metal lattices, netting or laths. Very thick sections or massive items require some technique for discharge of heat during hydration. This is done layer by layer application, use of cold water mixing, or colder atmosphere application. An entrapped heat quickens the rate hydration of wetted outer mass, but blocking the hydration of rest of the inner core mass. It may also crack the mass due to localized expansion.


For specific hard finish surfaces such as in commercial Gyp or Gypsum boards, the gypsum is completely dehydrated at high temperature, and with use of chemicals such as alkali sulphate, alum, or borax. For surface integrity fibres (short staples), semi digested paper pulp, lime or clay may be added to the plasters during manufacture. Gypsum boards are reinforced with paper or synthetic films on one or both sides.

Rodin Plaster form of The Three Shades

Many famous historical paintings in Europe are painted on a thin layer of wet plaster or Gesso. It is a white paint like coating of a binder gum mixed with chalk, gypsum, and sometimes a colourant, or any combination of these. It is preparatory surface for drawing or impressing outlines of artwork. The coating was applied on wood panels, canvas, sculptures and masonry walls and ceilings. Gypsum is used as a coating material over papier-mache forms.



CORRIDORS and PASSAGES Transfer Systems in Buildings (Part – IV ) Vasari Corridor of Florence

Post 277 – by Gautam Shah

CORRIDORS and PASSAGES IV Vasari Corridor of Florence


Vasari Corridor

An elevated and enclosed passageway of 1 KM length was built in Florence Italy in 1564, within a short period of 5 months. The corridor was designed by Georgio Vasari for the Grand Duke Cosimo I de’ Medici. The duke was feeling politically insecure, because he had replaced the Republic of Florence, and wanted a Corridoio between his place of residence, the Palazzo Pitti and the place of work, the Palazzo Vecchio (Duke’s Uffizi or offices). The need for a passage for incognito movements was acute, due to the wedding between Francesco I de’ Medici (Cosimo’s son) and Giovanna of Austria.

Vasari’s tile-roofed Corridoio running from the Uffizi (right) across the Ponte Vecchio on its way to link Palazzo Pitti

Vasari Corridor over the Arches

View from Ponte Vecchio from above

Close view of River Arno Bridge > Original meat shops were forced out and replaced with Goldsmith shops

The construction of a corridor with huge arches, between the residence and the government palace, located across Arno river, and over a densely populated Florence city, was not without its share of troubles. The resistance to passing of corridor structure over several private properties was scuttled, but had to skirt the Mannelli’s Tower, after the staunch opposition of that family. The smelly meat market of Ponte Vecchio was replaced with Goldsmith shops, which still occupy the bridge.

in the Bobli Gardens then a private estate

The Tower of Mannelli which was not allowed to be touched

Street view of the Ponte Vecchio as seen from the Vasari Corridor

Arch at street level underpass

The corridor had several well-placed small windows overlooking the streets and river it crosses. Mussolini in 1939 ordered corridor windows facing river Arno to be enlarged so that Florence visiting Adolf Hitler could enjoy the view. Hitler (the architect by heart) was impressed by the view through the windows, and later saw to it that bridge is saved from German bombing during World War II. All the other bridges in Florence were destroyed.

Pitti end

The Uffizi end of the Corridoio Vasariano (Vasari Corridor) is now used as an art gallery. This part was severely damaged by a terrorist attack of the Italian Mafia in 1993. Several artworks were destroyed, and those badly damaged have been pieced together and placed back on their original spot, to serve as a reminder of the incident.

The Corridoio seen from the Ponte Vecchio

After passing the Ponte Vecchio (market on bridge), the corridor passes over the Loggiato (arcade) of the church of Santa Felicita, here it had a balcony allowing Duke’s family to follow services without mixing with the populace.

Church Santa Felicita and corridor

Street and the Corridor above

The corridor was conceived as a raised private footpath for incognito movement, and so its entrance within the Uffizi Gallery is behind an unmarked or featureless door. Walking over the heads of the people below gives a feeling, as if spying over the streets, while remaining unnoticed. The 1 KM long passage was fairly long, for ordinary staff and royalty, so it is presumed the corridor had benches on the way for rest.


CORRIDORS and PASSAGES Transfer Systems in Buildings (Part – III ) Passages

Post 276 – by Gautam Shah



A passage is narrow space, defined by its consistent sides. Its linearity endows a sense of discipline and directional movement. Long processions have been part of ancient rituals, and the paths for it are defined by curbs, barricades, intermittent flag-masts, columns, statues or obelisks. The top side was bridged with buntings or hangings. Additional markings for passages were formed through steps and ramps or fronting objects like a building, gate or natural objects like a hill or mountain top.


The megalithic passage tomb at Newgrange in Ireland covers over an acre and was constructed around 3200 B.C. It has a long passageway formed by the side wall. At the winter solstice, the rising sun shines down the long passage and lights up a cross-shaped chamber.

temple of Hatshepsut

Egyptian Labyrinth whose only literary reference is by 1st C BC Greek geographer both had called it a great palace composed of many palaces. In front of the entrances are crypts, long and numerous winding passages communicating with one another. Egyptian temples had axial passages, stretching almost infinitely in front. Pyramids have had inclined passages, some leading nowhere.

Secret passages, also commonly referred to as hidden routes for stealthy travel, usually for emergency escape. The route, its entry and exit point, all require careful planning, construction, upkeep and secrecy.


Passages have occurred due to sheer massive movement of people. Roman amphitheatres and stadiums were designed for efficient ingress and egress of audiences. Entrance arches (marked by number) lead to a corridor that ran uninterruptedly around the building. The corridor led to staircases and passages to sections of seats. The passages were called the Vomitorium (plural: vomitoria). These were situated below or behind the tiers of seats through which the crowds could spew out at the end of a performance.


Buildings of Medieval and Renaissance period, mostly followed the Roman dwellings, with entry through Andito (small entrance area) or vestibule leading to a hall or courtyard. The courtyards were more prominent in Southern Europe but did not distribute the entry to rooms. Rooms were accessed from one to another. The courtyard and the corridor came together in southern monasteries, to create all sided circulatory space.

ref: PM_073858_E_So_Domingo_de_Silos; Claustro bajo o procesional, pilar del àngulo nordeste, cara oriental: relieve del Enterramiento de Cristo y la visita de las Santas Mujeres al Sepulcro, SXI

Vatican has a passage that is similar to Vasari Florence corridor. The Passetto di Borgo, or simply Passetto, is an elevated passage that links the Vatican City with the Castel Sant’Angelo. It is an approximately 800-m long corridor.




7 1024px-Rome_passetto_night_outside

Passetto, called in Roman dialect er Corridore Wikipedia Image by Carlomorino

Buildings of Medieval and later period began to reform the entry spaces, or more specifically the Halls into longer passages or long halls. The longer hall allowed several branch corridors or even rooms. The corridor was a long interior space, which needed illumination, ventilation and in colder climate warming up. It was a dreaded space, often haunted due to its capacity to prolong the reverberation. Yet, it was a preferred style of space. The gallery built by Francesco Borromini in 1635 Palazzo Spada, in Rome was, for a corridor much shorter. It sculpture much smaller. It was a false corridor of an optical illusion in only 8.5 mts of depth.


11 IMG_0403_-_Sant'Ivo_alla_sapienza

12 Antiquarium_residence_munich_hdr



Post 275 –by Gautam Shah





Alabaster has been used for decorative objects since 3500BC. It is believed that one of the sources for Alabaster was Alabastron, a town in Egypt. The Greek mineral name alabastrites is derived from that town. The word alabaster relates to Greek –alabastros or alabastos, and old French –alabastre. Alabaster also connects to ancient Egyptian word a-labaste that refers to vessels of the Egyptian Goddess Bast.



When cut in thin sheets, Calcite alabaster is translucent enough to be used for small windows. It was used for glazing (when glass was rare) in Byzantine and later in Italian medieval churches. Large sheets of Aragonese gypsum alabaster are used extensively in the contemporary Cathedral of Our Lady of the Angels, Los Angeles, in 2002. It requires special cooling to prevent the panes from overheating and turning opaque. There are several examples of alabaster windows in ordinary village churches and monasteries in northern Spain. Translucent alabaster is used for craft items like lamps and chandeliers.


‘Calcite, like most carbonates, will dissolve with most forms of acid. Calcite can be either dissolved by groundwater or precipitated by groundwater, depending on several factors including the water temperature, pH, and dissolved ion concentrations. Although calcite is fairly insoluble in cold water, acidity can cause dissolution of calcite and release of carbon dioxide gas. Ambient carbon dioxide, due to its acidity, has a slight solubilizing effect on calcite. Calcite exhibits an unusual characteristic called retrograde solubility in which it becomes less soluble in water as the temperature increases. When conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together or it can fill fractures. When conditions are right for dissolution, the removal of calcite can dramatically increase the porosity and permeability of the rock, and if it continues for a long period of time may result in the formation of caves. On a landscape scale, continued dissolution of calcium carbonate-rich rocks can lead to the expansion and eventual collapse of cave systems, resulting in various forms of karst topography’. (from Wikipedia).


640px-Alabaster_Bazylika_JGAlabaster is translucent whitish kind of gypsum. It is a soft and easy to work or carve material used for making vases, ornaments, bottles, jars, busts and ornamental objects. A three-foot vase with a relief from Warka, of 3500-3000 BC (in British Museum), busts from Sumer, of 3000 BC (Louvre), ornate triple lotus oil lamps found in the Tomb of Tutankhamen 1356 BC, and Sarcophagus of Seti I 1304 BC, are some ancient items made of alabaster. Decorative artefacts of Alabaster have been found in Sumer, Babylonia, Assyria and Roman empire. In later periods it was used in India from 6th to 13th C.


Alabaster are broadly two classes of minerals, a sulphate of lime or a pure variety of gypsum, and the other is a carbonate of lime, akin to a marble in composition. Due to the close resemblance of the two materials, in terms colour and grain, some ambiguity in distinct identification has persisted. The gypsum alabaster or the oriental alabaster is more softer, delicate and needs care in polishing. It soon tarnishes on atmospheric exposure, and affected by dust and smoke. The carbonate alabaster is little more firmer and so more suitable for larger items. This was sourced from caves where lime water drips to form natural deposits or moulded forms. It is also called onyx-marble or alabaster-onyx, or simply as onyx. There are several types of alabaster found, including pink, white, and black.

Pietà, 1440, Alabaster, Museum Frankfurt

600px-Norbury,_Derbyshire_-_Nicholas_FitzherbertAlabaster have been modified by various treatments. To make it opaque like a marble, its translucency is reduced by immersing the completed work in a bath of water, and gradually heating, so that stone does not become dead white or chalky. The treated material is called marmo-di-Castellina. Alabaster is also tinted to accentuate the natural veins or to add colour that matches the stone or wood in the surroundings. This is done to produce make-believe coral for decorative elements like rails of staircases, handles and trims.


Lioness_Bast_cosmetic_jar_83d40m_tut_burial_artifactAlabaster was used as translucent panels before the advent of glass, in openings of monasteries in Mediterranean countries, like Greece, France, Italy and Spain. Alabaster cut into thin sheets is translucent enough for dull interior illumination.



Inspired by dull glow of Alabaster panels, Thin Marble panels have been used as exterior wall units for Beinecke Rare Book & Manuscript Library Yale University in New Haven, Connecticut. Large alabaster sheets have been used extensively in a Contemporary Cathedral of Our Lady of the Angels, 2002 AD, The cathedral incorporates special cooling system to prevent the panes from overheating and turning opaque.





Post 274 –by Gautam Shah


Delhi Government Building with upper level Ventilator Windows for thermal management

Thermal management by WINDOW VENTILATION

Ventilation affects the heat level of an interior space, by addition, extraction or conservation. The heat exchange is managed by opening-closing of various sections of the window. Openings must be opened prudently, remain open or closed permanently. By scheduling (time or season), and by controlling the extent of opening, heat can be conserved or diffused in the building.


Thermal management by WINDOW DESIGN

The structure of the opening system is a thin body and so heat transfer through it is far quicker, then with any other component of the building. Thermal performance of a window is a function of three elements: glazing, frame and perimeter details.

Window Twins Prague

Thermal management by WINDOW DESIGN > GLAZING

Glazing is transparent to translucent material that allows transmission of heat across it. Its thin wall has low thermal insulation capacity. But glazing systems with multiple layers, cavity and modern e-coatings show improved thermal performance. Windows with lower U-factors or higher R-values perform better in colder climates, and windows with lower solar heat gain coefficients (SHGC) perform better in warmer climates.


Thermal management by WINDOW DESIGN >LOW-E COATINGS

Low-e coatings minimize the amount of ultraviolet and infrared light that can pass through glass without compromising the amount of visible light that is transmitted. It reflects long-wave infrared energy or heat and significant amounts of short-wave solar infrared energy. When during the winter, interior heat energy that tries to escape colder outside, the low-e coating reflects the heat back to interior space, reducing the radiant heat loss. A reverse process occurs during warmer days. Low-e coatings are applied directly on the glass or as coated plastic film. Such coatings are inevitable part of the multi layered double / triple glass glazing units. Here Low-e coatings are applied to one glazing surface facing the air gap of the insulating gas unit.

Reflective Glass Building Chicago


Reflective particles deposited on glazing materials of clear, tinted, or otherwise treated varieties. They generally reduce visible-light transmission, but are less effective for curtailing infrared radiation. Like mirrored glazing, they cause annoying reflection over neighbours’ buildings, which often causing a heat build up there. Frit is the most common angle-selective coating. It consists of a ceramic coating, either translucent or opaque, which is screen-printed in small patterns on a glass surface. The pattern used on the glass controls the light based on its angle of the incidence. The colour of Frit controls the reflection or absorption and the control of view or visual privacy. Visual transparency can also be controlled by applying Frit to both sides of the glass so that at some angles it appears transparent, and at other angles it appears opaque.

Frit Glass


Directionally selective materials reject or redirect incident solar radiation based on a geometric relationship between the radiation and material. Such glazing can redirect light to a predetermined location. They include glass blocks, silk-screened glazing, prismatic devices, enclosed louvres, holographic films, and embedded structures.

Paris Glass Building Reflections Facade


Dynamic glazing is called switchable optical windows or smart windows, because the photo-chromatic properties of the glazing can be altered with change in level of illumination or by an electric current. Dynamic glazing also includes polarized glazing materials, which with a change in its inclination curtail view and light (as in rear view mirrors of automobiles). Switchable materials can provide glare reduction, privacy, daylight and solar control, and reduction of ultraviolet transmission.



The frame of the window, its materials, geometry and method of fabrication (e.g. thermal breaks in metal frames), determine thermal behaviour of the opening system. Low conductance materials, such as wood, vinyl, and fibre glass, perform better than high conductance materials such as aluminium or mild steel. Perimeter details of commercial or low-cost windows are extremely poor and have high thermal leakage across joints. High end windows have rubber gaskets, polyurethane fill-in and other thermal breaks (layers of insulation materials that isolates the internal and external surfaces / components). These need to be continuously checked and replaced. Proper placement of insulation material in the voids at the window perimeter and maintaining continuity of the air barrier reduces drafts and energy loss around windows. It is not possible to separate the inside and outside faces of a window completely, as the frame and shutter each are of single body construction. A complete thermal isolation can be best achieved by having two sets of windows placed as non touching entities.

640px-Fenster_-_DreifachverglasungThermal management by WINDOW DESIGN > JOINT DESIGN

Windows are multi component systems with many joints which cause leakage of energy. Windows are now tested and rated for air tightness. A rating, of 0.2 cfm/ft (cubic feet per minute of air leakage per linear foot of window edge) or lower, is considered good. A good window has a rating of 0.1 cfm/ft or lower. Windows with low-emission and solar control coatings, low-conductance gas fills, improved thermal breaks and edge spacers, and better edge sealing techniques cannot be taken granted for the thermal performance. The manner of fixing at the site can alter the thermal behaviour of the window. A window well made and properly fixed at the site still needs to be periodically maintained, as the thermal breaks have a very short life cycle (requiring frequent replacement).


Thermal management by SHADING DEVICES

These are designed to take optimum advantage of seasonal orientation of solar incidences. The solar gain occurs primarily in reference to the plane of the window, so an alternate method could be to have a variable plane of the window, but that may be architectural style-wise, not a very viable option. However, external shading devices keep the glazing surface in shade, while cutting off the direct solar radiation. Shading devices such as Venetian blinds or vertical louvres are not very effective on the internal face of the opening, as the solar gain has already been admitted into the interior space. But interior shading devices offer glare control, and visual comfort.

O Niemeyer building with shading devices


Space planning and scheduling of tasks, are the occupants’ only recourse for thermal management in ready to use spaces. These are required in rigid architectural planning where all faces of building are identical or space units can be sited to just any orientation. As a way out new occupants reset and reschedule their life, to match the available openings related climatic facilities. This is not an easy solution to implement Interior Design intervention for the occupant or their interior design expert.

Shading by siting and scheduling -Kutchh Gujarat India



Post 273 – by Gautam Shah



A systems thinking is way to discipline, an organization. Its a way to look at an entity’s constitution or structural system and a functional or purposive system that is realized only during the operative conditions. A singular system holistically serves an unique purpose, and so its structure and purpose are spatially and temporally one, whereas in multi-lateral systems, the purposes are served at several space nodes and time segments.

Organization and Composition



Open or Closed systems have between them a very simplistic difference. But, it can have different connotations depending on who considers it. People concerned with buildings, architects, interior designers, structural engineers, builders, promoters and occupants all have completely different understanding of the concept. To compound the problem, many Systems Thinking ideologies from other fields are being implicated here. Some of these include: Components and Systems approach, Holistic or Unified approach, Prefabrication and Modular coordination, Dimensional coordination, Dimensional preferences, System building, Industrialized building, etc.

MODULAR PLANNING Richards and Goddard research labs by L Kahn

MODULAR PLANNING Richards and Goddard research labs by L Kahn

Designers see the space design as bubbles or doodles of function modules each recognized with non-material barriers, and of proportional extent. This is a mental process and manual expression, of the intents. It needs conversion to the site, through drafting tools. To persist with all these ethereal ideas through dimensions, material definitions, style, etc., and more importantly for confirmation by all stakeholders is a difficult endeavour. One misses the overall implications of it, as systems thinking. Only clarity that comes through is by delineation of space delimiting elements and space servicing elements. The elements that form these two categories are mutually not exclusive, so a cohesive system without gaps, overlaps or repetition must occur.


Holistic form of Building


Here two thinking styles distinctly emerge. Designers evolve holistic design thinking, where, things become parts or components only by the constructors. The holistic or monumental form celebrates the designer, but fails to recognize the user. Other set of designers’ who participate with all stakeholders, (interior designers, structural engineers, builders, service providers, promoters and occupants ), create a system or framework for contribution. Buildings with very large footprints and community concerns cannot take any other route. The stress on building of nodes, boundary conditions, connectivity, dimensional and modular coordination (ISO 2848 Modular Coordination -Principles and Rules), is inevitable into Open-ended systems thinking.


All systems are defined by their edge conditions, be it real, virtual or hypothetical. The edges when breach less, create a holistic or closed ended entity. But with nodes or the breaches, an open-ended system emerges. A node (Latin nodus =knot) is a connection point, a redistribution point or an end or terminal point.


Modulated or unitized architecture of Computer system

Computers operate as a single system linked with other systems, including other computers. However, here the concept of single system goes further, whereby other connected systems mutually share their resources. Unlike grid computers, clustered systems have an intermediate or middleware (hard and soft) that functions in time and space.




Openness is said to be the opposite of secrecy. It is not just free unrestricted access but a synergy for collaborative working. Systems are classified as Open systems, when transition of mass and energy, occurs across the edges, such as water pond, building or earth’s atmosphere. A Closed system has no scope for mass transfer but may exchange energy across the border such as gas in a balloon. A system is called an isolated or insulated system when it is not dependent on exchange of mass or energy. Some take the classification further; a self-sufficient system is one which subsists on its own enthalpy.



This following note on Open-ended and Closed ended system was published in one of my Blog >> OPEN ENDED vs CLOSED ENDED SYSTEMS https://interiordesignassist.wordpress.com/2014/04/21/open-ended-systems-vs-closed-ended-systems/



In an open-ended system, components designed or manufactured by different vendors are used. The success of such a system depends on the adaptation of measures, standards for materials and codes for procedures. Open-ended systems are wasteful because of the built in reserves or additional capacities. The built in capacities in the open-ended systems do facilitate future replacements, improvisations and up-gradations. Open-ended systems generally result from mature and multi trial endeavours. Where large number of people are involved in design and execution and where these processes are likely to take place in different time spans, the system automatically becomes open ended. Open-ended systems are also called ‘open architecture entities’.



In a closed ended system the components are not interchangeable. Components designed for a particular situation are neither usable nor adoptable in another situation. Closed systems are very wholesome or compact compared with open systems, which usually have a skeleton type frame structure (infrastructure) and are loosely held. Closed systems are rigid and not easily improvisable, whereas open systems allow up-gradation. Closed ended system being compact, have no redundancy. Closed ended system become totally useless with even minor changes in their environment or working. Close ended systems generally result from first ever (prime) or unique creative effort. Spontaneous and one man creations tend to be closed systems, unless a conscious effort is made to make it an open system. Closed-ended systems are also called ‘proprietary systems’.


FOOD PREPARATION SYSTEMS – VII -Kitchen facilities and tasks

Post 272  –by Gautam Shah



The kitchen became a very complex space system, because many services from outside had their first port of linkage here. Things like fuel, water, commodities, deliveries, family members, staff and strangers, all arrived at kitchen because these were intensively required here and taken care of. Similarly kitchen was point of disposal and departure for the same reasons.


The only thing that was not desired in the ancient kitchen was the dining and guest entertainment by the house master. This was the chief reason why it remained neglected, till the quality of food and related services failed to impress the guests. Kitchen was un-owned or non-personal space, managed by a paid servants. Contrasting to these the kitchens of crafts person or farmers were lively and participatory spaces. These were often the only and real living rooms, with the attic as the isolated space for the master.

Bath tub

The kitchen gradually became a space system that housed several facilities and amenities to conduct not only food preparation related tasks, but washing, bathing, craft-work, and personal interactions. In colder climates families of ordinary citizens had dining as part of it. In warmer climates the kitchen and dining together served to be an interactive family space. The kitchen was conducted by the housewife, and she presided over it, even in societies the family was supposed to be subservient to the chief male of the house. Nobody would challenge the house-wife’s exclusive domination in kitchen.

White Kitchen

The exclusive supremacy of the wife was however, taken away in few countries or cultures, where women were forced to be in purdah. The kitchen as a connected space to the outside world was considered too promiscuous. An isolated kitchen can keep the affairs of family insulated from the out-side influences. The out-house kitchen was isolated from women’s quarters and conducted by Khansamas or male cooks. Large mansions of 18th C, Lucknow, Raipur, Bhopal and later the British officials’ bungalows had out-house kitchens (Bavarchi-khana) for different reasons. The separation of the kitchen from the house offered freedom from heat, odours and smoke.



Kitchens, from Industrial revolution era, have become effectively dependent on outside resources. Every thing that a kitchen needed, such as the fuels, condiments, commodities, partly prepared foods (tinned foods), water supply, solid and liquid waste disposal, gained substantial efficiency from such outside dependencies.

The kitchen now began to be arranged on the basis of such dependencies on the world outside. The dependencies manifested outside, so were touched upon on the perimeter of the kitchen. The internal arrangements reflected the external resources.

Wall dependency for amenities and facilities

The utilities are placed at resourceful locations. The utilities and their siting created a task routing pattern. Siting and Routing both added to higher productivity in the kitchen processes. Day by day, the spatial contribution of the building, and the connectivity of utilities, provided for many other technological developments.

Bath tub in Kitchen

Just as Industrial production was being streamlined into timed linear processes, late 19th and early 20th C women groups and magazines demanded work efficiency considerations in kitchen planning. These resulted in the recognition of wonder triangle of productivity, with nodes for sink, freeze and stove and total distance covered 6 to 6.5 mts.

Walled kitchen