MEANING of CRAFTS -5 -TOOLS

Post 651 -by Gautam Shah

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Tools are implements used by a person in manual operations for production or processing, like manipulation materials, craft-work, building construction, cultivation, food processing, offense-defence, handling, carriage, measurement and expression (writing, drawing, enacting). Tools have been used for making better tools. Tools are for doings things in an easier manner, as well as for doings things that otherwise would not have been possible by hands. There are few conditions where instead of the tools, the supports and other facilitatory structures and arrangements help in creative efforts and productivity.

Tools are universal implements, used over different tasks and materials. Over a time, though, an exclusive manner of handling develops. The manner of handling evolves a holding mechanism. The holding mechanism, an entity integral with the tool, allowed efficient use of the tool. The combination of a tool and its handling mechanism was a task (and material) specific facility. The tools and handling section, each served different purposes, and so were shaped accordingly. Both faced different stresses and required different composition. But a combination of diverse forms and materials need to be compatible, coordinated and well joined.

 

Handled tools extend and modify the reach of the body. The extended reach helps remote access, adds to leverage and allows torque or twisting. For cutting, breaking, beating, copping and such other jobs need leverage for impact or percussive forces.

A lever amplifies an input force to provide a greater output force. The lever arm is defined as the perpendicular distance from the axis of rotation to the line of action of the force.

Recognizing objects that can work more efficiently was the first craft. Refining by reshaping natural objects for a specific purpose has been one of the oldest craft industries. Some of the basic craft tools were for food preparation, and personal safety and security. Early tools were fragile and often got consumed in the use-processes. And so, the search for new tools was everlasting, alternatively new tools had to be fashioned from old ones. Redefining the tools necessitated search for better materials, sharpening the edge, and tying a handle.

Tools were now of three basic classes: hand-held tools, percussive tools and projectiles. Other sub-classes were like cutting, scrapping, hole making, vessels, holding, measuring, coating-spreading, digging, mixing, etc.

Primary tool materials were stones, woods, bones, clays and perhaps metals. Some of these could be re-formed by downsizing. Clay and metals were plastic materials that could be re-formed by moulding and additive process.

Holding tools became important for two main purposes, to hold fine-sized objects and tools and to hold fire or hot things. Fine items like beads, and precious-stones need to be held properly to work upon them. Tool bits like fine and fragile edges need support, whereas fine points for drilling and engravings require adequate gripping. Tools were required to initiate, and work with fire. These included fire-fuel management utilities (chulhas), air blowers, handle for hot tools and holders for vessels. Agriculture related tools like thresher boards, winnowing baskets, sieves, land tillers, etc. Spinning, knitting, and weaving utilities developed for threads and cordage, which were used for binding handles, roof and wall elements, fishing nets, etc.

Tools, as said earlier, are handy things. But there are many utilities, facilitatory structures and arrangements that have helped creative efforts and productivity. In these, at certain level of detail tools like appendages or similar advantages are invested. One of the first ones was the fireplace that contained the fire, helped efficient use of the fuel and offered resting stands for things to be heated. Similarly structures were created as dwelling spaces, clothes or apparel, shoes, head caps, adornments, toys, totems, murals, shutter systems over openings, hangers for food to protect it from insects and rodents, sleeping mats, hammocks and cradles, lamps that evolved less heat but more light, food grinding stones, narrow neck pitchers for liquid storage, slide for transporting goods, etc.

At some level the tools, utilities, facilitatory structures and arrangements were merged as devices, machines, apparatuses, equipments or plants. These were integrated with the built-forms, for support, location-based advantage or task setting. The tool, craft and technology were one seamless pursuit. The pursuit also integrated several materials into not only single purpose entities but very specialized task facilities. The task related specializations also created technology-based castes, guilds and communities. The craft communities are tied to terrains and climates. This allows them to develop acutely ethnic styles.

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LINKS on BLOGS relating CORRIDORS and VERANDAHS

Post 650 -by Gautam Shah

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TRANSFER SYSTEMS

CORRIDORS

CORRIDOR SPACES

CORRIDORS AND PASSAGES (Part – I)

CORRIDORS AND PASSAGES -as Transfer Systems in Buildings (Part – II) DESIGN PARAMETERS

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

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

VERANDAHS and equivalent architectural forms

VERANDAHS and equivalent architectural forms Part – II

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REFERENCING buildings -issues for design -15

Post 649 -by Gautam Shah

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Buildings are nominally referenced by way of orientation, alignment, linkages, front-back placement, ground-line (gravity) or datum, framing, etc. Such references site a building location, set a direction, form relationships with surrounding elements, confirm the flow of energies like gravity, magnetism etc. and with it generate the sense of horizontal (parallel to the flow of energy) and vertical (towards-against the flow of energy). In this sense Referencing achieves a sense of balance, stability, steadfastness, belonging, scale, proportion and comparison.

Referencing is recognition of relationship between objects and persons in the context of the environment or the surroundings. Such recognition is a basal instinct. We mainly visually discern the size, direction, distance of objects and comparative details of objects, but these experiences are reinforced through other sensorial references like hearing, smell, touch, tastes etc. We also experience referential effects of energy like gravity, magnetism, electricity, etc.

Reference, derives from Middle English referren, from Middle French référer, from Latin referre, formed from the prefix ‘re and ferre’. Other derived words carry the sense of link-to, connect to, to carry back, to deliver, consult, an allusion, signs, indication, mention.

References can take on many forms, including: real and measurable, ephemeral like a thought, metaphysical like an allegory, sensory experience, manifestation of energy, a geometrical pattern, crypto-graphical conversions, or a part of a sequence or order.

In architecture references occur explicitly, subtly and metaphorically. Explicit references are superfluous or add-ons like enrichments, embellishments, stylized forms, with little relevance to functionality. Explicit references denote an overwhelming urge to make the ‘form follows the function’. Subtle references in built forms are innate, with deep rooted cultural connections like customs. The logic is integral in the social fabric, and no justifications are offered or expected. Subtle references in architecture have restricted relevance, available only connoisseurs, experts or practicing colleagues in the field. Subtle references require perception of a whole entity, as available in abstracted orthographic presentations such as plans, sections, elevations. Subtle references often connect to things or incidences that are in different time and space. Metaphoric references relate to abstracted representations. The layers of abstractions or coding are many and their trace complicated, so a metaphor seems to stand alone. Metaphoric references become a language of variegated forms. It is a pattern in its own entirety, like an alphabet where original phones or images have very remote connections.

References have hierarchical structure where parts and components of the entity itself mutually relate, and also associate with other objects in the same or different time and space. Metaphoric expressions in architecture link expressions in other fields, or allude to such thoughts and concepts.

Architectural references are formed intentionally, accidentally or unknowingly. Intentional references are part of the design creation process, so could be as justification for something that is uncommon. Accidental references are realization on a hind site. These actualize after drawing documentation, graphical representation, scaled-model making or through actual execution. Architectural references unknowingly become relevant, in some other context, because such effects were not perceived, or some unknown connection emerges through other media.

Architectural references are explored to reinforce or dilute a concept, and focus or divert from a composition. References are used to enforce or negate the essential elements of a style or theme. Just as enforcement occurs through repetition, highlight, scaling or linkages, negation needs occlusion, elimination of details and restraint. Holistic compositions though have singular but very emphatic expression, whereas assemblies formed by single person or organization have some basic consistency, with noticeable reference.

Reference in architecture is often literal, and so easily perceptible, like representation of birds, animals, objects, etc. The process of revelation however is made little more complex due to several layers of conversion or negotiations. Grotesque forms, humanoids, demons, devils, beasts, monsters are such conversions, where each representation becomes more complex with age and graphics making technologies. Yet robots remained replicas of humans or animals with head, eyes, hand and legs for several decades. Martians or aliens are still humanoids.

For architectural forms, the domineering factor has been the gravity, and the related sense of horizontality versus verticality. Gravity is part of our being conditioning all our creations, and it has taken years to move away from the gravity related prevalence, in conception of outer space modules. Gravity refers to stability, and anything wider at the base is safer and permanent and so monumental. Similarly, any reverse position is challenging and so celestial. For the same reason Ground-line or Horizon becomes very important base line for a building to relate to. Real or notional reference to ground-line is always assuring.

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This is the 15 th article of 20 topics series on ISSUES for DESIGN

PASSIVE VENTILATION in Buildings

Post 648 -Gautam Shah

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Passive ventilation sustains good quality of air in interior spaces. It works on circulation or movement of air without the use of power utilities. It relies on principals of source management and dilution, rather than any filtration. Passive ventilation is substantially based on the quality of built-form and to a smaller extent on immediate surroundings. It is a very important method of adjusting heat and moisture in Hot-arid and Hot-humid climates. The quality of air is determined by temperature, moisture content, presence and proportion of ‘other’ gases and airborne particulate matter. The quality of air has important bearing on our body. A body may endure or adopt to certain abnormal conditions for a period of time but there may occur side effects. The side effects may be realized in a different form and at a different time.

Passive ventilation relies, as much on external or macro conditions, as the interior spatial lay. It is based on three factors:

1. Air movements due to the differing pressures and temperatures and the buoyancy forces that result across a building and its surroundings,
2. Location of tasks and activities that support or hinder such patterns of air movements, circumstantial and designed apertures in the building shell.
3. Factors that define the ventilation in a building are, space-profile (section), base levels of inward-outward nodes of ventilation, nature of surroundings and neighbourhood, sill level, depth and its profile-shape, task-intensive operative plane and its volume, and constraints enforced by elements such as size and shape of external overhangs.

Passive ventilation occurs with Two major operants.

● Differential air pressures are formed by wind movements in the immediacy of the building, the pattern and size of the buildings scheme and individual components of the building. Air movement also occur as a buoyancy effect caused by the temperatures of surfaces and surroundings near the wind-ward and wind-off sides. Air pressure difference occurs, across buildings’ interiors and exteriors, across the openings and temperature of surfaces and surroundings, near the windward and wind-off sides. Entry and exit point for air, though continually shift around due to the changes in pressures.

● Temperature differential depends on the direction and inclination of sun, climate, seasons of the year, local massing of the shadows, surface materials, vegetation, water bodies, and presence of heat evolving entities. Dark surfaces and thin body objects warm up very fast and begin to radiate the heat, creating local heat related buoyancy in air.

Ventilation requirements vary depending on whether one wants to gain or lose heat, add or subtract moisture, dilute or remove ‘other’ gases and airborne particulate matter contaminants. Ventilation needs change depending on, distance of space occupation from the inlet-outlet for air, functional use of space, types of tasks, work-schedules, crowding in the space and presence of heat evolving means (hearths, machines, etc.). One important aspect is the feeling of air movement near-over the body. It depends on several factors such as air velocity, fluctuations in air velocity, temperature of air, and personal factors like overall thermal sensation and activity level. Even for the same person, sensitivity to air movement may change from day to day.

Draughts (Draft) are very low velocity air movements. These are not always perceptible, as they do not cause any sensation of pain or pressure on skin. Draughts are more felt due to air pressure thresholds near cracks and such leakage points in small and enclosed spaces. Draughts, however, help in convective heat exchange, evaporation and dilution of pollutants in air. Draughts cause localized cooling or heating of sensitive organs of our body.

Breeze or low to medium velocity air movements generally affect only local areas. Breeze does not let airborne particulate matter to settle down. Skin sensation can be avoided by appropriate screening and deflection of the breeze. Since breeze causes effective pressure on skin, with very immediate and very perceptible change sensation.

Winds are high air velocity movements of air affecting larger regions. Winds raise particulate matter in the air, cause rapid change in level of humidity and often cause discomfort due to high pressure sensation on the skin.

In hot and cold both types of climates people often close all the openings to reduce the air movements and thereby control the convective heat gain or loss. Turbulent air velocity is less comfortable than a Laminar air velocity. Turbulent air movement achieves a better mix of air whereas laminar helps in greater displacement of air mass. This is the reason why in hot arid climates small size openings are used to create turbulence or a viscous flow, and in hot humid climates the body level openings of horizontal nature create a laminar flow to displace the humidity.

Passive ventilation occurs through macro and micro openings. Macro or formal openings (doors, windows, gaps etc.) are designed with a characteristic size, shape, passage section, adjunct elements on internal and external faces, and occur close to the location of need (for ventilation). Micro openings are circumstantial, and are much smaller in size like cracks, crevices, gaps or apertures. Micro openings offer a passive and consistent ways of managing comfort in enclosed and semi-open spaces. These manifest as intentional gaps, unplanned crevices and cracks of structural stresses. Both, macro and micro openings can be broadly be classified by their locations.

• Roof level openings are such as in the thatched and country tile roofs, loosely laid roof slates, stone sheets, or intentionally placed micro passive vents such as lattices, chutes, hoppers, etc.
• Upper section openings in walls are such as the unpacked ends of corrugated sheets or roofing tiles, ends of purlins and truss and eyelets or oculi like holes and lites in gables.
• Other openings manifest as doors, windows, cut-outs, chowks, in joinery, leaky fitments, ajar shutters, door bottom space, peep-holes, latticed constructions such as of woven mats or fabrics, louvered openings, crack or fissures in building elements, expansion joints, unsealed joints, etc.

Movement of air through openings encourages evaporation and increases cooling in the interior space. In dry arid climates dwellers locate their activities in the strongly directional air movement formed by small and deep-set openings. Deep-set openings also increase absorption of heat in the mass of the structure. Simple passive cooling devices such as water wetted grass mats or fountains help cooling. Outside air has lesser moisture (except during raining conditions) then indoor air, so any level of ventilation, dilutes the interior humidity level and adds to the comfort.

Air borne particulates arrive from outside sources like heavy vehicular traffic, polluting industry (mines, thermal power plants, mineral grinding plants, in the vicinity, or sand storms, and internal sources like cooking or craft fuels, and processing materials (grinding, spinning-weaving). Outside particulate can be controlled by changing the ventilation gaps to different location or elevation. Filtration screens occupy more then 60% of opening area, and much lesser due to frequent choking. Dynamic screening like water bodies or sprays can be useful, but costly and perhaps beyond the concept of a passive device. Non turbulent wind flow helps in keeping the particulate matter to lower sections.

Moisture control in interior space occurs by dilution, greater air movement and siting management of moisture generating amenities. Isolation of cooking, washing, bathing areas in dwelling is a common practice in hot-humid climates.

Quality of indoor air mainly depends on the external circumstances. The ‘feel-good aspect’ in a tropical climate (hot-arid or hot-humid) zone is not only regulated by the obvious temperature, rates of movement (pressure) and the moisture content, but also by the level of fouling of air. Some experts have claimed that air quality of a room is chiefly determined by its CO₂ concentration. In tropical buildings concentration of CO₂ and other gases is not a critical factor, as numerous openings and micro gaps remain substantially open. Location of cooking area is a segregated entity or an outdoor activity, and like cold climates no interior fire places.

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