Construction Hoist compare domestic and international standards

A country's development and construction elevator problems

In recent years, the development of construction hoist is mainly reflected in the appearance of improvement, weight reduction hoists, lifting speed and altitude increase, hoists amount of load increases, improved safety devices and electrical control automation and so on.

Steel, aluminum, aluminum plate and other lightweight materials are used to make the cage weight greatly reduced, in order to reduce the required power transmission mechanism, users save energy created conditions; while hoists drop weight and frequency stepless speed technology commonly used, and also allows hoists lifting speed can be improved; domestic anti-braking load 60kN successful development of safety device for an increase in the amount of load hoists provide a guarantee; hoists powered using transmission slip line so lift height broke the 450m; in electrical control, semi-automatic and fully automatic floor call, hoists stop layer unmanned accurate electronic control system has been tested in a mature and extensive use of export products; construction elevator varieties more and more. It can be said that China's development and construction elevator technological progress, basically to keep up with the beat of the international industry, fully able to meet the needs of the rapid development of the construction industry and has been exported.

However, in the cage load power ratio, reliability and lifetime of components, product design and the use of the concept of security and other aspects of domestic and international advanced level compared to the lifts there are still many gaps, these gaps have resulted in our construction hoist national standards with international advanced standards gap.

2 construction hoist national standards with international advanced standards gap

2005 edition of "Construction Elevator" national standard revision, we have carefully studied the international advanced European standards (EN12159: 2000) and American Standard (ANSI / ASSE 10.4 - 2004). We'd love "is equivalent to" use (identify) European standard, or at least "equivalent" use (equivalent), but unfortunately can not be achieved due to various reasons, is a "modification" use (modify), of which the most important is the overall level of the industry and habits, philosophy (mostly from users) gap. Because different national conditions, some gaps (for example, in the case of unmanned stations can summon each layer cage, it runs automatically and accurately stop layer; each landing must be installed in place by the cage door unlocked layer) can suspended with the international advanced standards, and following gaps should be with the international advanced standards.

2.1 pairs of cage floor space limitations

European standards, according to the cage Rated load 100kg determined by dividing the number of persons carried hoists, each covers an area no larger than 0.25m2; U.S. standards for various rated load hoists the maximum floor area of   clearly defined, its purpose is a capacity to prevent overcrowding and ensure safety. At rated load 2 000kg of hoists, for example, by European standards hoists the maximum floor area of   5m2 (1.5m wide, the length is not greater than 3.33m), by American standards cage floor area not exceeding 4.25m2 (1.5m wide when length not greater than 2.8m). In China, in order to meet more users can be loaded dump truck, 2 000kg amount contained in the cage are required to be made until 1.5m × 3.5m 1.5m × 4.2m, which is very safe, because on the site rush hour, hoists passengers are packed. 1996 Edition Construction lifts GB in pairs cage floor space only requires minimum unrestricted caps, 2005 construction elevator GB we can only write "hoists can be manned number of rated load divided by 80kg, rounded tail rounded", " When the cage is used only manned occasions, per capita land use should not exceed 0.25m2 ", why this provision does not cover all of them dual-use goods lifts, because the standard of review when the strong opposition from the user's behalf. Some may think, 2007 edition of "Construction Elevator Safety Regulations" after the implementation of the cage should have overload protection, and then a big cage, the crew will not be overloaded. However, in the development of standards, we must consider the protection of device failure or, in some cases, artificial lift the protection device may - consider "just in case", and user regulations, this is Europe, America's most prominent ideas advanced standards.

2.2 hoists lifting speed limit

Working conditions for maximum lifting speed hoists, American standard regulation 91.44m/min, Europe, and none of our standard provided for (but limited to the current safety device maximum operating speed of only 2m / s, but also to enhance the speed hoists no more than 102m/min). Conditions for the installation of hoists the maximum lifting speed, the European standard specified as ≤ 4 2 m / min (U.S. standard is ≤ 4 0 m / min), the 2005 edition of the standard also provides for the construction elevator ≤ 42m/min (0.7m / s). Lifts OEMs should check their manual, whether expressly provided by GB installation conditions hoists lifting speed.

2.3 Installation conditions hoists rated load limit

Even hoist rated load (working conditions) and then a big, installation conditions of the amount set out in the European standard regulation ≤ 1 000kg (U.S. standard is ≤ 800kg), our failure to make the required standard. As we all know, during the installation process, machine parts (including safety devices) are not fully loaded, the cage should not enter the normal load condition (otherwise, it is a working condition), so that "no installation of hoists for heavy working conditions amount of load is the amount set out their work conditions "is wrong (if the installation conditions of the rated load capacity of the transmission mechanism mistakenly come to be, then the speed is greater than 42m/min lifts, installation conditions as follows lifting speed ≤ 42m / min, it can exceed the carrying capacity of the work conditions of the amount of load). In order to ensure safety, working conditions hoists installed to restrict the amount of load is necessary.

2.4 Loading and unloading of additional force

Cage door threshold and the threshold level (or the boarding platform edge) of the design strength, loading and unloading should be considered vertical force generated when the horizontal force FV and FH, European standards: FV cage should be 50% of the amount of load F, but not less than 2kN, and when F is greater than 20kN, FV = 4 +0.3 F (kN); FH F shall be 20% but not less than 0.5kN, nor more than 2.5kN; FV and FH (as concentrated loads) while acting on the cage floor entrance and exit of the 1/3 width Department. This requirement is very reasonable, our standards should be included.

2.5 Product standards should require product life

In the construction elevator, tower  hoist crane  revision of national standards, for "Do not use the accident was scrapped" considerations, the drafting group that deal with product life make provision - is based on scientific judgments waste load cycles, the product plus equipment suitable irreversible logger, if unable to do so widespread and effective use of recording devices may require the judge waste year. But both proposals are ultimately not adopted.

As altitude dangerous work product, does not require its service life, reducing and avoiding accidents is very unfavorable. European standards for construction elevator concept is this made life: "manned lifts basic load cycles shall be taken as 1.6 × 105 - intermittent operation (ie 10 years × 40 weeks / year × 40 hrs / week × 10 cycles / hours). " This stipulates that the number of load cycles, also made useful life (10 years). European product used in each 1 600h, life expectancy is only 10 years. In China, according to the lift working day 240 days, working 10h, then 10 years of load cycles is 2.4 × 105, life should not exceed 10

Year (by European standards and less than 7 years). We believe that the inclusion of special equipment products, should provide its service life. In other conditions do not taste of the case, even to use the number of years of life does not belong to specify arbitrary. At present, China has many products to life as a basis for judgment waste, such as waste gas water heater life sentence of 6 years (date of installation). In all sorts of desperation, 2005 edition construction lifts the inclusion of Shi GB

Workers lift machine working level. 2005 edition of "Construction lift" GB 5.1.4 stipulates that the person dual-use goods construction elevator machine working level A5 ~ A6. For ordinary people who under normal use dual-use goods lifts, load cycles is taken as 1.25 × 105 <CT ≤ 2.5 × 105, according to GB / T 3811 " bridge crane  design specifications", the use of class U4, load status is taken as Q3, Thus the whole working-level A5 (special, heavy work status of the whole working-level desirable for the A6, specifically determined by the manufacturer).

Since construction hoist the national standard has not yet clearly defined life, to ensure the safe use of lifts in some provinces and cities building department has begun planning for the long era of specialists in lifts for safety assessment. For example, the provisions of the relevant departments of Shanghai tower  hoist crane , construction hoist evaluation period, that the whole working-level A5 product, after 10 years of use reassessed annually (including ultrasonic flaw detection, thickness measurement profiles, structural stress testing, etc.); A6 machine working level products for 15 years after an annual basis. Thus many OEMs issue a certificate to user requirements, all construction elevator machine working class as A6. Product-level machine work must be carefully identified, should be selected based on the work of product design level truthfully reply, otherwise it would be safety hazards exist, the user ultimately irresponsible.

3 Conclusion
In summary, our current construction hoist the national standard is behind the international advanced standards, although the 2005 construction elevator GB version has been incorporated into a number of European and American standard content, but overall there is a gap.

Greatest experience of the European standard, the standard setters fully consider the case based on the idea of   possible (or even misuse will occur) security risks, so as to formulate effective targeted preventive measures. Our product designers, product standards setters, the use of on-site managers, we must first learn, adhering to is this people-oriented, safety first concept and implementation in practical work. Same time, through the whole industry is constantly striving to further improve our product design, manufacturing quality and on-site scientific management level, which is the standard of our products as soon as possible with the international foundation. Existing national standards have not been prescribed some security restrictions or requirements directly related, OEMs and enterprise standards should make provision for product manuals, to ensure the safety of construction lift assembly and disassembly, use, maintenance; majority only the design, manufacture, management, and use of consensus in order to become the national standard and is consciously implement the provisions.