Design principles for viewing windows and pool portholes
A Roman author, architect, and civil engineer Vitruvius was undoubtedly right, asserting that a structure must be solid, useful and beautiful. Over the course of history, the Vitruvian Triad represented the very essence of creating an architectural object both in the antique times and present high-tech period. The project planning of swimming pools is quite a considerable and complicated part of pool creation and it also has to meet the above-mentioned requirements.
The up-to-date equivalent of the word “useful” is “functional”. Pools are intended for water sports, swimming training, rehabilitation and relaxation.
Size, shape of a pool and engineering equipment are approved according to the purpose of the pool. In the modern situation, an increasingly wide application in the project development and modern pool construction is given to underwater windows and glazed pools.
Initially underwater (or viewing) windows were used as an additional control method for water sports coaches and trainers and served for observing the people who train in the water. Coaches could observe the movements of athletes and control the actions of divers, staying dry and gaining insight at eye level. Glass pools are implemented in sports up to now for training, officiating and keeping up a running commentary of water sports, such as water polo, swimming, springboard diving, synchronized swimming, etc. Apart from that, glass pools are also used for shooting music videos, advertisement videos and photoshoots.
The latest edition of "Architectural Engineering and Construction Code. Pools for Swimming. (SP 31-113-2004)" outlines the basic guidelines for installation of viewing windows and portholes in the walls and bottom of pools. For now, these rules have been elaborated only for indoor 50m-long pools and specialized diving pools: “p.1.4.49. Viewing windows are recommended to be 0.4-0.5 meters high and 1-2 meters wide:
- Viewing windows for diver monitoring are recommended to be located at a distance of 3-3.5 m from the pool wall with diving boards; viewing windows for swimmer monitoring are recommended to be located along the spine walls of a pool and not closer than 1-1.5 m from the end wall.
- Underwater illumination lamps are placed in the ports between the viewing windows at a depth of 0.65-1m below water level at a distance of approximately 4 m from one another.
- To access the viewing windows and portholes, approaches of minimum 1.2-1.5 m wide and 1.8 m high should be provided.
- As concerns the construction of portholes and underwater viewing windows, tempered glass is recommended.
As you can see, the information is quite insufficient in the homeland published sources, but the subject is constantly developing.
Besides sports pools, there are pools for swimming training, therapeutic and wellness pools, pools for diving and other public and private swimming pools. In most cases, the glazed underwater elements (underwater or viewing windows, portholes) are simply a functional necessity. Underwater windows are included in the rehabilitation and physiotherapy pools: they allow medical personnel to observe the patient's behavior in the pool, as well as to study and coordinate his movements.
As for other types of pools, it is safe to say that pool glazing brings many advantages and improves the use of the pools.
Domestic manufacturers use world technologies and adapt them to specific objects, making original design and taking into account the peculiarities of the particular construction. Elaboration on design and management of underwater glazing multiplies due to the contribution of technologist and engineers.
It is obvious that the characteristics of the materials used for underwater glazing are a very important factor responsible for the strength and durability of any construction. In the modern interpretation this concept includes not only structural integrity and stability of the structures (cast-in-situ walls and bottom of pools, reinforced concrete supports, or, for instance, glazed units), but also safe operation and maintenance, durability and resistance to different factors. Proper integration of glazed components with the main structural elements of the pools, the use of advanced glazing and sealing materials – this is the key to a safe, convenient and long-term exploitation of the construction.
There are two main ways to install viewing windows into the pool basin: the first is the installation of a ready-made window unit (in a stainless steel frame) and the second is the installation of an acrylic panel (without a frame) into a concrete wall.
The first method of installing underwater windows into the pool walls and bottom is not technologically complicated, but distinctive. Such constructions presuppose the use of special shock resistant glass (Triplex, Duplex) or implementation of acrylic glass. Windows frames are made of marine grade stainless steel of V4A/316L type and manufactured in accordance with industry standards of quality. The construction of the window presupposes some additional place for temperature expansion, retaining, though, its waterproofing quality between the window itself and a wall. In some technologies, the stainless steel is used for underwater window parts (which contacts with water) and overwater (dry) parts. Rubber seals used by experts do not age, and they retain their properties even when exposed to sea water and chemicals used in swimming pools, so they eliminate any leakage.
Thus, rectangular windows minimum dimensions are 400x400 mm and grow in width and length with the step of 200 (100) mm. Maximum dimensions of a typical window are limited by 2800 mm in width and 1800 mm in length. Round windows have the following dimensions: minimum diameter is 400 mm and maximal – 1800 mm. Sizes change with the step of 100 mm. At the request of a customer, windows can have individual size.
It should be mentioned that the dimensions of the window (width, length and thickness of glass) have to correspond to the depth of installation. The thickness is individually calculated and adapted depending on the depth and water pressure; it can vary within 30-100 mm range.
As concerns mounting underwater windows and portholes, it is of great importance whether the window is installed into a horizontal (wall) or a vertical (bottom) surface. The first case presupposes installation of a viewing window strictly in the vertical plane flushed with a pool wall. When installing a viewing window in the bottom of the basin, it should be mounted true-horizontally. The most popular types of finish are tiles and glass mosaic.
The second kind of acrylic panels mounting is quite interesting, progressive and at the same time very simple. This method is more cost-effective and provides more freedom in choosing the underwater window size. Since the acrylic glass is mounted directly into the opening of the wall, you can make the most of the dimensions of a standard sheet 2000х3000 mm. If necessary, acrylic sheets are welded together at the molecular level, creating a heavy-duty connection, to get longer acrylic panels. Acrylic (polymethylmethacrylate, PMMA) is a high strength material with the optical transparency which surpasses the parameters of glass (92%). for the time being, acrylic is the most transparent material. All visible seams and joints of the sheets are also transparent – this is a prerogative of acrylic only and cannot be provided by any other material.
When casting pool basins, the openings in the concrete structure are supplied with a frame (a groove in the bottom side and quarters on the rest three sides). An acrylic panel filling is performed with a bevel along the perimeter of the construction. The dimensions of panels are smaller than the opening as much as a technological gap is. The bottom groove and quarters are determined by the thickness of glazing and reliability of the overall structure. All technological gaps are filled with gaskets and waterproof compounds that fully meet the characteristics discussed in the above-mentioned method. Planeta Neptuna Company experts, given the size of windows and the depth of installation, make required calculations for structures and joints, and propose the most appropriate solutions to ensure the integrity and leak-proofness of the acrylic panels.
Installation of underwater windows and portholes is possible both in the newly constructed and reconstructed basins of swimming pools. The only difference consists in that the reconstructed swimming pool will require more careful and cautious approach and the implementation of maximum size glazing in any place will be subject to additional charges.
And the last, but not the least, concept is esthetical point.
People that visit a swimming pool are not likely to be interested in the peculiarities of underwater windows construction or ask about the panel thickness. Water sports coaches, cameramen and photographers are not fond of technical issues either. what will have value for them is the visible architectural elements, quality of finishing, underwater windows size and their location, and other esthetical details which constitute an integral image of the pool. We shouldn’t omit here a great variety of possible material combinations, shapes, methods of glazing that can be implemented in modern pools. It is obvious that the implementation of underwater glazing or construction of an acrylic structure will create a memorable and individual image of the whole architectural object.
Summing up all above-mentioned, one can now imagine the relevance of underwater glass basins implementation and the wonderful possibility of inventing and realizing impressing projects of partial or full glazing of pools, and installation of viewing windows and portholes. It is possible nowadays due to new advanced technologies and improved high quality materials.
The conclusion is forced upon you. Each segment of the architectural and construction market, which includes underwater glazing pools, fully meets the three basic concepts mentioned earlier: solid, useful and beautiful. Harmoniously, properly designed and installed acrylic windows and portholes – it is never too much of a good thing for an up-to-date swimming pool.
When it comes to design, construction and maintenance of underwater glazing panels, Planeta Neptuna Company is always willing to provide technical assistance or take part in the process of your exclusive pool creation.