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The handrail is a traditional building component in the architecture.

In traditional architecture, handrail does not participate in the force system of the entire building, but handrail has a very successful shape in architectural art. With the evolution of the building itself, as well as the improvement of science and technology, materials, and people’s aesthetics, the handrail has also been greatly developed, and a variety of forms have been developed.

Features worth mentioning are:

  • The traditional wood
  • Stone
  • Brick
  • Ceramic handrail
  • Iron
  • Stainless steel handrail
  • Aluminum alloy
  • glass railing
  • Nylon steel core combination
  • PVC and other materials

There are various shapes and beautiful shapes. In modern construction projects, the design and application of handrail are indispensable.

Stainless steel handrail not only plays a role in safety protection but is also a building component for beautifying buildings, providing conditions for designing and creating beautiful buildings. But no matter how gorgeous buildings are, the safety of building components must be guaranteed.

Therefore, the country has promulgated corresponding building codes and product standards, giving certain safety requirements for the design and application of handrail and product production. Architecture is closely related to the vital interests of the people. Only a clear understanding of the concept of handrail safety protection can better grasp the direction in design and application.

In residential buildings, stainless steel balconies, stainless steel indoor stairs, inner patios, outdoor fire-fighting stairs, low windowsills, ramps for the disabled, roof protection, verandas and other parts that need handrail, the mechanical properties, protection height and structure of handrail at different parts There are relevant regulations on the requirements. In terms of material selection, the impact of corrosion resistance on life should be considered. The following discusses the mechanical properties, protection height, structural requirements, and material selection of the handrail.

1. Mechanical properties

In real life, a handrail is often relied on, supported by people, leaned against, high-speed collisions, handling collisions, etc., so the handrail should be made of strong and durable materials, but because the force requirements of the handrail in different parts are not the same.

According to the mechanical performance requirements specified in “Glass and Metal handrail for Buildings”, combined with handrail in residential building application parts, the details are as follows:

Option 1.1 – Horizontal load for stainless steel handrail

Regardless of where the handrail is applied to the building, the requirement that the handrail can withstand the horizontal load not less than 1.0kN/m should be considered. The main reason is that as long as people go to the place, there will be situations such as relying on and climbing on the handrail, so the safety of the handrail must be ensured, and the performance requirements of the handrail must not be reduced due to the places where there are few people.

Option 1.2 – Vertical load for stainless steel handrail

In residential balconies, inner patios, roof protection, outer corridors, etc., the handrail between the two columns of the handrail (the distance between the columns is not greater than 1.2m) is required to bear a vertical load of 1.5kN. According to the requirements of the “Building Structure Load Code”, the handrail bears a vertical load The load is not less than 1.2kN/m, which is equivalent to two people who can fully carry the weight of 75kg, which is 95% of ergonomics. Mainly according to people’s daily habits, the handrail in these positions is all lying on their backs, and some people even sit on the handrail. Therefore, it is necessary to consider the effect of vertical load, especially for side-mounted handrail structures, the consideration of vertical load design is particularly important.

Option 1.3 – Soft and heavy object impact for stainless steel handrail

In residential balconies, inner patios, roof protection, outer corridors, etc., the handrail between the two columns of the handrail (the distance between the columns is not greater than 1.2m) is required to bear a vertical load of 1.5kN. According to the requirements of the “Building Structure Load Code”, the handrail bears a vertical load The load is not less than 1.2kN/m, which is equivalent to two people who can fully carry the weight of 75kg, which is 95% of ergonomics. Mainly according to people’s daily habits, the handrail in these positions is all lying on their backs, and some people even sit on the handrail. Therefore, it is necessary to consider the effect of vertical load, especially for side-mounted handrail structures, the consideration of vertical load design is particularly important.

Option 1.4 – Impact performance of hard and heavy objects

Wherever the stainless steel handrail in the residence is, as long as the handrail adopts the glass handrail structure, it should bear the impact of hard and heavy objects. The weight of the solid steel ball is 1040g±10g, the landing height is 1.2m, and the swing arm hits the handrail glass.

It adopts swing arm impact, which can more effectively imitate the effect of the handrail being hit. It mainly prevents the glass from breaking after the impact of ordinary hard objects, which will cause unnecessary safety to people. Hidden dangers.

Option 1.5 – Stainless steel handrail wind pressure requirements

Outdoor handrail in residences have windward balconies, roof protections, verandahs, etc., and the fence structure is glass or metal plate, which needs to meet the load under the action of the local wind pressure index value.

2. Protection height

With the development of my country’s national economy and the improvement of people’s living standards, the height of people, especially young people, is generally increasing.

Therefore, when undertaking the design of handrail protection height, the handrail protection height specified in the building code should be taken as a minimum value. Control and appropriately increase the height of the handrail protection. The height of handrail and window sills and reasonable structural measures have a significant impact on the safe use of buildings.

Designers need to fully understand the corresponding building codes involved in residential design and express the various requirements of the handrail in the building codes on the design drawings. clear. Avoid unnecessary hidden dangers and ensure the safety of people’s lives. The protection height requirements of different parts of the handrail in the residence are not the same. The following is summarized according to the relevant provisions of the “General Principles of Civil Building Design”, “Code for Residential Design” and “Code for Barrier-Free Design”:

  • The handrail protection height (clear height of the railing) for the balcony, veranda, inner patio, and the upper person roof, the flying height is less than 24m (lower and multi-layer), the handrail protection height should not be less than 1.05m; the flying height is 24m and above ( The height of the handrail should not be lower than 1.10m.
  • The handrail protection height of indoor stairs should not be less than 0.90m, and the handrail protection height of outdoor stairs should not be less than 1.10m.
  • When the length of the horizontal section of the stairs is greater than or equal to 0.50m, the protection height of the handrail shall not be less than 1.05m.
  • When there are two levels of the handrail on both sides of ramps, steps, and stairs for the disabled, the handrail protection height and handrail position height is 0.85m and 0.65m respectively.

The determination of the handrail protection height is particularly important in the safety protection of the handrail. The following is an analysis of how to determine the handrail protection height (rail net height).

Option 2.1 – Stainless steel balconies, outer corridors, inner patios, indoor corridors, handrail at the roof of the Master.

From the perspective of ergonomics, the height of handrail protection should be higher than the center of gravity of people, and people feel safe. According to the “General Principles of Civil Design”, the anthropometric results of 14 provinces in my country in 1980:

The average height of men in my country is 1656.03mm, and the height of the center of gravity of an adult in an upright state is 994mm, and the height of the center of gravity after wearing shoes is 994+ 20 = 1014mm.

Therefore, in the “General Principles of Civil Design GB 50352-2005”, it is stated that the height of the handrail protection should not be less than 1.05 when the height of the balconies, outer corridors, indoor corridors, inner patios, upper roofs, and outdoor stairs is less than 24m. The height of the handrail protection should not be lower than 1.10m when the flying height is 24m and above, including middle- and high-rise residential buildings.

In the “Code for Residential Design” and “General Principles of Civil Design”, it is required that the protection height of balcony handrail of low-rise and multi-story residences should not be less than 1.05m, and the protection height of balcony handrail of middle-high-rise and high-rise residences should not be less than 1.10m.

When determining the design height of the enclosed balcony, some designers think that the balcony is closed and has the same function as a room, so the height can be designed according to the height of the window sill, and it is only necessary to ensure that 0.90m. This taken for granted does not comply with the “Residential Design Code” Article 5.6.4 requires that the enclosed balcony handrail should also meet the requirements of the balcony handrail protection height. Mainly because the enclosed balcony does not change the requirements of the human body and the body’s center of gravity. In design practice, it is often to increase the inner area of ​​the suite and select the north-facing balcony as the kitchen part. Although the balcony is closed in design and construction, it should be considered as 1.05 m high.

The necessary safety protection requirements cannot be changed. In order to avoid potential safety hazards, the protection height of other enclosed balconies should also be designed in accordance with residential requirements. The protective height of the balcony handrail should increase with the increase of the building height.

Determining the treatable area: According to the “General Principles of Civil Building Design”, when the width of the bottom of the handrail is greater than or equal to 220mm, and the height is less than or equal to 450mm, it is the position that can be stepped on; The lower part is a platform with a height not greater than 450mm. When the width of the platform on the inner side of the handrail is greater than 65mm, the platform should be regarded as a stable part; according to normal people’s stepping conditions, people can easily step on and stand and look out instead of climbing.

At this time, the handrail protection height If it is calculated from the floor or roof, the height of the top surface of the handrail will be lower than the height of the center of gravity of the person, which is very unsafe, so it should be calculated from the top surface of the readable part (Figure 1).

It should be noted that the protection height of the handrail is determined according to the national standard GB 50352 and related international standards, which refers to the height of the handrail obtained according to the specified requirements after the installation of the handrail product on the project; the height of the handrail is the height of itself, Is the distance from the base of the column to the upper surface of the handrail;

However, some handrails are higher than the handrail, and the handrail plays a protective role to a certain extent. However, according to the regulations of “Glass and Metal Handrail for Building”, the handrail is higher than The upper surface of the armrest is not used as a protective position.

Option 2.2 – Stainless steel handrail at the stairs.

Stairs are divided into indoor and outdoor stairs, and their requirements are different.

The height of the handrail of indoor stairs should not be less than 0.90m measured from the front edge of the step. When the horizontal handrail on the side of the stairwell exceeds 0.50m, its height shall not be less than 1.05m. It is because when the length of the horizontal section exceeds 0.5m, people can rely on the handrail here.

At this time, the center of gravity of the person must be considered, so the requirement should not be less than 1.05m. In the “Code for Fire Protection Design of Buildings GB 50016-2014”, it is required that the height of the handrail should not be less than 1.1m when the outdoor stairs are used as evacuation stairs. The outdoor stairs are suspended outside the main building, and the handrail protection height exceeds the center of gravity of the person, the more people feel safer, so the building code gives a height of 1.1 meters.

Determining the treatable area: According to the “General Principles of Civil Building Design”, when the width of the bottom of the handrail is greater than or equal to 220mm, and the height is less than or equal to 450mm, it is the position that can be stepped on; The lower part is a platform with a height not greater than 450mm. When the width of the platform on the inner side of the handrail is greater than 65mm, the platform should be regarded as a stable part; according to normal people’s stepping conditions, people can easily step on and stand and look out instead of climbing. At this time, the handrail protection height If it is calculated from the floor or roof, the height of the top surface of the handrail will be lower than the height of the center of gravity of the person, which is very unsafe, so it should be calculated from the top surface of the handrail part (Figure 1).

It should be noted that the protection height of the handrail is determined according to the national standard GB 50352 and related international standards, which refers to the height of the handrail obtained according to the specified requirements after the installation of the handrail product on the project; the height of the handrail is the height of the handrail itself, Is the distance from the base of the column to the upper surface of the handrail; however, some handrail is higher than the handrails, and the handrail plays a protective role to a certain extent. However, according to the regulations of “Glass and Metal Handrail for Building”, the handrail is higher than The upper surface of the armrest is not used as a protective position.

Option 2.3 – Stainless steel handrail at the low window sill

When the window sill near the sky is less than 0.80m, protective measures should be taken. The protective height should not be less than 0.80m from the floor. Take protective measures; when there is a wide window sill at the lower part of the low window sill, bay window, etc., where people can stand on, the protective height of the window handrail or fixed window should be calculated from the window sill.

The “Code for Residential Design” requires that when the height of the external window sill from the floor and the ground is less than 0.90 m, there should be protective facilities, and there is no such restriction when there is a balcony or platform outside the window. The clear height of the window sill or the protective height of the handrail shall be calculated from the treatable surface to ensure a clear height of 0.90m.

Tabletops and railings below 0.45m from the building (ground) surface that can easily cause unconscious climbing should not be included in the net height of the window sill. For the bay window sill in our residential design, because there is enough area for people to stand on it, for safety, the height of the window handrail should be calculated from the window sill.

There is also a case where a fixed fan and safety glass is used within 0.9m of the lower part of the bay window, without a handrail. From the aesthetic point of view, no handrail will make people feel more comfortable and transparent, but the fixed fan safety glass here usually uses hollow laminated safety glass. The laminated glass part is two layers of 3+3+0.38mm thick Glass is insufficient for safety protection and cannot be used as a handrail.

Option 2.4 – Handicapped ramp

Taking into account the needs of humanity, the current “Code of Residential Buildings” requires that the entrance and entrance platform of the building be designed to be barrier-free, in order to facilitate the use of abductees and the visually disabled. When there are steps at the entrance, wheelchair ramps and handrails should be provided. The ramps and steps for the disabled shall be provided with a handrail with a height of 0.85m. When there are two levels of the handrail, the height of the lower handrail shall be 0.65m.

3. Construction requirements

In the design of handrails, we should not only pursue the perfect effect. In the construction, we should also pay attention to the following points:

Option 3.1 – Penetration of the handrail

The penetrability of the handrail not only needs to prevent the human body from passing through the handrail, but also prevents jamming or falling, and also prevents ground objects from rolling down through the handrail, causing people and objects downstairs to be smashed.

3.1.1 If the handrail is a rod structure, the net distance between adjacent rods should not be greater than 110mm; if the handrail is a glass or metal plate structure, the handrail and the column, the handrail and the handrail, the handrail and the ground, etc. The gap should not be greater than 110mm; if the handrail board is a steel cable or steel mesh structure, the cable spacing or grid should not allow the steel sphere with a diameter of 110mm to pass.

Mainly based on the principle of ergonomics, the structure gap in the handrail is too large or too small, and children are easy to get out, causing unfortunate accidents or jamming children’s hands or feet. The sphere inspection is mainly to imitate the human head and test the fence structure with certain expansion conditions to ensure that the head does not pass through the gap to ensure the safe application of the handrail.

3.1.2 Side-mounted handrail, the distance between the edge of the fence and the ground should not be greater than 30mm

Description:

  • the ground;
  • The distance between the edge of the fence and the ground.

It should be understood that children often play against the handrail. If the gap at the bottom of the side-mounted handrail is too low, the child’s feet will get stuck in the gap, or there is a risk of falling through the body.

3.1.3 The handrail should not be left empty within 0.10m of the height of the floor (treatable surface) and the roof. Its purpose is to prevent small rolling objects on the ground from slipping from the ground gap; at the same time, it acts as a water barrier.

Option 3.2 – Climbability

For residential handrail, when one side of the handrail has an overhanging height greater than 0.8m or is in a dangerous zone, the handrail should take measures to prevent children from climbing to prevent children from playing slide games on the handrails and causing fall accidents.

Option 3.3 – Object fall prevention

When placing flower pots or other objects on residential balconies, roof guards, and outer corridors, fall prevention measures should be taken to avoid accidents caused by falling flower pots or other objects.

Option 3.4 – Equipment on the handrail

When balconies, roof guards, and outer corridor handrail are equipped with solar components, relevant safety should be paid attention to and corresponding protective measures should be taken:

  • Photovoltaic handrail, take measures to prevent leakage and lightning. Equipment such as electricity storage is not allowed to be installed on the handrail.
  • Light and heat handrails should be made to prevent scalding and dripping. The handrail is not allowed to be used as water pipes, and water tanks and other equipment are not allowed to be installed on the handrail.

Mainly, solar balcony handrail is used on balconies, which are the most commonly used places in people’s daily life. The handrail structure can be frequently contacted. The solar balcony handrails have the function of solar energy conversion. After conversion, they have different substances such as electricity or hot water. Therefore, safety requirements cannot be ignored. Water tanks and power storage equipment are large in size and are energy storage equipment. They are highly dangerous. Installation on the handrail will cause greater safety hazards.

4. Material selection

When selecting materials for residential building handrail, we must pay attention to corrosion resistance, and make requirements for commonly used materials according to “Glass and Metal handrail for Building”.

Option 4.1 – Stainless steel handrail

The stainless steel material should be austenitic stainless steel, the chemical composition should meet the relevant requirements of GB/T 20878, and the Ni content should not be less than 8.00%, and the Cr content should not be less than 16.00%. The main materials used are conventional materials such as austenitic stainless steel 06Cr19Ni10, 06Cr17Ni12Mo2, 022Cr17Ni12Mo2, which are widely used in the construction field, have good corrosion resistance, good maintenance, processing, and mechanical properties, and beautiful surface.

It is not to say that only austenitic stainless steel materials can be used for handrail, and other stainless steel materials are not suitable for use. For example, ferritic stainless steels are not as good as austenitic stainless steels in terms of corrosion resistance, but they are used for an indoor handrail with the surface finish.

Electroplating treatment improves the decoration and corrosion resistance of the surface, and also has a good use effect; ferritic-austenitic stainless steel (duplex stainless steel) has corrosion resistance equivalent to that of austenitic stainless steel but has With better mechanical properties, the application of handrail has also been continuously expanded, and better application effects have been obtained.

In the application of austenitic stainless steel, there are two hot topics-stainless steel rust problem and stainless steel strip magnetic problem, the following two problems will be analyzed.

4.1.1 Stainless steel rust problem

The corrosion resistance of stainless steel depends on chromium, but because chromium is one of the components of steel, the protection methods are different. When the addition amount of chromium reaches 10.5%, the atmospheric corrosion resistance of steel is significantly increased, but when the chromium content is higher, although the corrosion resistance can still be improved, it is not obvious.

The reason is that when chromium is used to alloy steel, the type of surface oxide is changed to a surface oxide similar to that formed on pure chromium metal. This tightly adhered chromium-rich oxide protects the surface and prevents further oxidation.

This oxide layer is extremely thin, and the natural luster of the steel surface can be seen through it, giving stainless steel a unique surface. Moreover, if the surface layer is damaged, the exposed steel surface will react with the atmosphere to repair itself, re-form this “passivation film” and continue to play a protective role; but it is not completely rust-free.

Whether it is rusty is affected by various factors such as its molecular structure, processing technology, and use environment. Rust on the surface is not like the rust of carbon steel, which has rapid damage to the substrate, but a kind of rust that grows on the surface.

Within a certain period of time, there is no damage to the substrate and can be removed by wiping or cleaning with chemicals. This type of rust, commonly known as “floating rust”, has many reasons for rusting, mainly due to atmospheric environment, construction environment, and product maintenance. The key to improving the anti-rust ability of austenitic stainless steel lies in maintenance and maintenance.

Stainless Steel Handrail Application

It has good rust resistance under the following two conditions:

  • Reduce surface roughness. When the surface roughness Ra is less than 0.5 µm, the surface is easy to clean. , The residual harmful substances on the stainless steel surface will be reduced, thereby reducing the possibility of rust. The roughness of the mirror surface is lower than Ra and less than 0.1µm, and the surface is smooth and has no obvious unevenness. When polishing is added, the surface is Wax, forming a dense passivation film, which has a strong anti-rust ability.
  • Electrolytic polishing is carried out after mechanical polishing. The electrolytic polishing solution contains a passivating agent. After electrolytic polishing, a thicker passivation film is formed on the surface of stainless steel, which improves the corrosion resistance of the surface. The corrosion resistance is better than mirror light. One point, general mirrors are not electropolished.

4.1.2 Magnetic problem of stainless steel strip

Not all stainless steels are non-magnetic, but only austenitic stainless steels have non-magnetic characteristics. However, under the action of cold working, it may lead to a certain degree of magnetism. After austenitic stainless steel is processed by bending, stretching, welding, etc.,

The structure will also transform to martensite. The larger the cold working deformation, the more martensite transformation and the stronger the magnetism. If you want to completely eliminate austenite The magnetism of bulk stainless steel can be restored to a stable austenite structure through high-temperature solution treatment, thereby eliminating magnetism.

Stainless Steel Handrail Application

Option 4.2 – Structural steel handrail

The surface of structural steel should be treated with effective anti-corrosion and anti-rust treatment measures; the copper accelerated acetic acid (CASS) test should be longer than 16h, and the surface should not have defects such as pinholes and blisters. The anti-corrosion and anti-rust measures of the surface should include the treatment of the inner wall surface of the steel pipe, not just the requirements of the outer surface.

Studies have shown that because the inner wall is difficult to surface treatment and the treatment cost is high, in the applied handrail, the handrail products made of carbon steel pipe have not undergone the inner wall surface treatment. In some outdoor handrails, due to the humid environment, the inner wall of the pipe becomes damp.

It is not easy to dry, causing corrosion from the inside out. The protective layer on the outer surface looks intact, but it has actually been severely corroded. According to research, the corrosion rate of unprotected low-carbon steel in the chloride-containing marine environment is 0.15mm per unit area per year. If there is no protection, the corrosion will continue to progress, and the material will soon appear serious thinning.

Therefore, after a certain period of time, the pipe wall has been corroded, causing the handrail column to break, which poses a greater safety hazard. Many accidents of this type have occurred. For example, on January 23, 2016, a woman in Chongqing fell to her death while watching snow on the balcony of the 24th floor due to a broken handrail. In order to avoid potential safety hazards, when choosing carbon steel pipes, the surface anti-corrosion measures of the inner and outer walls of the pipe must be required, and the service life of thinning due to corrosion must be fully considered.

Stainless Steel Handrail Application

Option 4.3 – Aluminum alloy handrail

The base material of aluminum alloy profiles should comply with the relevant regulations of GB 5237.1. When surface treatments such as anodizing, electrophoretic coating, polyester powder spraying, fluorocarbon spraying, etc.

Option 4.4 – Glass railing

The glass for indoor railings is equipped with columns and handrails. The railing glass is installed as an inlaid panel in the handrail system. The railing glass should be laminated glass specified in this regulation; the railing glass is fixed on the structure and directly bears the human body. , Its barrier glass should stipulate: when the lowest point of the barrier glass is not more than 5m from the ground of one floor, the toughened laminated glass with a projected thickness of not less than 16.76mm should be used; when the lowest point of the barrier glass is above the ground of one side When it is greater than 5m, this type of handrail system shall not be used. The following distinguish between handrail systems that directly bear the human body and handrail systems with columns and handrails:

Stainless Steel Handrail Application

4.4.1 The structure of the handrail system that directly bears the human body:

4.4.2 handrail system structure with columns and handrails:

Outdoor (balconies, roof protection, verandas) fence glass should be designed to resist wind pressure. For areas with seismic design requirements, the combined effect of seismic action should be considered and should comply with the provisions of this regulation.

Stainless Steel Handrail Application

5 – Summary

In modern residential buildings, handrails not only play a decorative aesthetic effect, but it is important that handrails take on the role of structural safety protection. In the design of handrail, the comprehensive and systematic design should be carried out from the aspects of mechanical properties, structural safety, protection height, material safety, and decorative aesthetics of the handrail. Of course, it is not enough to just have some specifications and standard parameters and requirements. It still needs the cooperation of handrail designers and material research units to continuously explore the application of handrails in residential buildings, summarize and improve relevant technical standards, and then continue to design. It is safe, applicable, durable, reliable, beautiful in shape, and has good social and economic efficiency.

How to install the stainless steel railing