The sense of sight or vision is perhaps the most influential among the five senses. Spectacular, marvelous, magnificent, splendiferous, wow, etc.; there are many verbal expressions to convey the appreciation for the beauty visible through our eyes. Our fascination with the joys that this ‘sense of vision’ can evoke is the basis for designing unique and awe-inspiring envelops for the buildings The façade industry has gone through many evolutions over centuries.
The industrial revolution has played a major role in bringing up the best in the façade industry and each of its segments. Between the start of the usage of glass in large areas of the façade in circa 16th century and the era of digital manufacturing in the 21st century, many revolutionary developments have been witnessed.
Functionally, a façade separates the indoor environment from outdoor. So, a façade and its components should be designed to withstand environmental factors like wind pressure, heat and cold, entrainment of water and air, harmful UV rays from sun, etc. Due to the supremacy of the ‘sense of vision’, the façade designers became the driving forces behind modern buildings.
Birla Vanya, Kalya
The compelling need to strive for the best of shapes, forms, colors and textures combined with innovative products and methods paved way for the realization of complicated designs and detailing. Advancements in designing facilitated by modern computer aided designs of the building envelop created requirements for customized hardware as well. The global markets for hardware industry in the due course have easily coped up with the demands of façade designs by using innovative materials and methods.
Modern buildings are mainly cladded with glass, aluminum, stone, wood, GRC, GFRC, etc. The function of building, area of application, environmental parameters, cost factors, etc. decide the type of façade to be implemented. Integration of glass and aluminum is abundantly used due to its multiple advantage and availability. Transparent panels and openable panels were also considered as essential requirements. Stick systems and unitized panel systems are commonly used by designers in the field of construction.
Openings in façade are required to allow interaction between the indoor and the outdoor environment in a controlled manner. Traditionally, punched windows were used to provide interior and exterior views, ventilation, regulate the transfer of humidity and sound. Door openings are required for secured entry and exit of man, material, vehicles, etc. Adjustable window openings are essential to ensure safe indoor climate conditions. Manual or automatic operable windows are commonly used in the current times.
Different façade systems require different hardware. For unitized panel systems, embedded U channels are used to connect façade to parent building. The load from the façade is transferred to the connected edges of the building through “U” channels.
Fixity of these channel is generally determined by the strength of the concrete, embedment depth, mechanical properties of the channel, method of installation and workmanship. It is commonly observed that the channels are displaced or misaligned during concrete pour. The top of the channel is required to match with the top surface of the slab. Bad workmanship can lead to the channel being covered with the concrete. Construction field engineers should therefore ensure that the channels are restrained properly before the concrete pour.
Pre and post concrete survey should be made mandatory. Extra care should be ensured during the use of needle vibrators near the channels during the pouring of the concrete. Negligence should be avoided as well as the urge to be overconfident. In case of mishaps, one needs to overcome hesitance to seek expert advice and ensure corrective measures. Mechanical and chemical properties of embedded channels should also comply with the specifications. Durability is a key factor to be considered while choosing the right product. Necessary tests should be conducted as per the project specification before continuing with successive activities.
T bolts are used to connect plate anchors to embedded channels. T bolts should be designed to resist the support reactions from façade design loads like Embedded U channels (Image courtesy – Hilti and Halfen) self-weight, wind, seismicity, thermal and occupational loads. High strength T bolts of same manufacturer of U channel should be used to ensure maximum efficiency.
T bolt and U channel provide tapered locking connection. This system allows flexible connection without the drilling process. While selecting the T bolt and channel, one must ensure that the fire rating requirements are met. High corrosion resistance is considered extremely important.
Unique systems of brackets are required for stick and unitized systems. Brackets are connected to embed U channels by using T bolts mentioned earlier. Brackets should be designed to withstand structural stresses from the façade. Slotted holes of the bracket help to accommodate the permitted deviation in plump of structural elements in different levels. Metallic covers may be used to protect the connection assembly from construction debris or impurities. Strict quality control should be assured during the installation of façade supporting hardware.
There are higher chances of overlooking these assemblies as a result of access restrictions to slab edge due to certain safety concerns. Remember, the density of glass is more than that of concrete. So, if the façade panel is disconnected from the slab edge, it could lead to major accidents.
Designers decide on the variety of windows based on various parameters. Horizontal sliding, vertical sliding, side hung casement, top hung casement, bottom hung casement, tilt and turn, pivot, bi-fold and louvered are some of the different types of windows in the modern market. The type of hardware differs according to the type of the window. However, irrespective of the type of windows, the common parameters to be considered are safety, security, durability, ease of use, and aesthetic value.
Screws, bolts and expansion shield are the basic components required for the installation of windows. Ideally, the finish of exposed fasteners should match with the finish of connecting member. One must ensure compatibility of fasteners with the material it passes through. The threaded steel fasteners should comply with Indian standard IS 1367 (Part 3). The numbers, spacing and location have to be pre-determined/ designed. Tests prescribed in the code should be conducted.
Sliding window locks and latches are normally operated with fingers. Space in the latch slot to insert fingers must be verified for the convenience of different age groups and different physiques. Ideally, RAL color code of lock should match with frames. Numerous options are available for the handle and lock of hung windows. Operating a window is a day to day affair. Functionality and ease of operation should be the prime factor rather than pure aesthetic appearance.
Unitized panel installation in one of Turner’s projects
At times a sleek design may not be durable. Actuation of the handle facilitates the closing and opening operation of the windows. Motorized operation is also possible if required. Side hung windows can be fitted with simple turn handles or handles with lock keys. Aluminum or stainless steel hardware is ideal for the coastal environment. Powder coated finish matching with the frames or metallic plating like chrome, satin, brass, nickel or stainless steel finish or anodized finish are the major finishes available in the market.
Hardware of aluminum doors are similar to that of the windows. Nevertheless, the choice should be based on the function of the room. “Security” is the word which comes into our mind when we think about the doors. Hence, door hardware should be selected carefully by considering the function of the room to be accessed. Multipoint security locks and key cylinders should be selected from reputed brands to avoid malfunction of locks. The reference code of Indian standard for door handle is IS 4992: 1975. The major hardware of doors are:
Lever/ Pull / knob handles
Every developer should pre-plan their hardwares selection by preparing hardware schedule in advance. Sample board of each type of door should be made available from the manufacturer/ supplier. The matrix should include type, style, function, size and finish of each item. Similarly, name of the manufacturer, location of use, and keying info should be indicated. Master keying must be decided in advance. Separate master key may be prepared for the main tower common areas, utility areas, mechanical areas, electrical rooms, machine rooms, etc. Also, one must ensure attic stock of minimum 5% of each component for future use. Manufacturer warranty should be ensured.
Globalization, market competition and innovative materials have given numerous choices to the customers to select the right hardware that suits their requirement. Good brands have been concentrating on continuous improvement of quality and increasing the product range to ensure sustainability of their market share.