Lift Report

The total number of passenger elevators in Germany is estimated to be about 630,000. About the half of them are more than 30 years old. Modernization and rehabilitation of these units will be needed in the future. The volume of work is estimated to be about € 500 million per year. The law, as currently written, does not mandate modernization of existing elevators. But the operators of these systems are nonetheless required, as prescribed in the following regulations, to keep the system as a whole and/or its components up to the state of the art:

The operator has to ensure that the elevator is being operated according to the state of the art (“Owner’s responsibility”, Section 12 of the Ordinance). “Operation”, as it is construed here, includes repairs, maintenance and rebuilding work that will have to be undertaken without delay. The state of the art will have to be incorporated into the modified system components whenever changes or thoroughgoing changes are undertaken.

A technical rule for operating safety, TRBS 1121 – entitled “Changes and fundamental changes in elevators” – has been worked out by the UA6 “Elevators” subcommittee; it is subordinate to the Operating Safety Committee (ABS). TRBS 1121 was adopted in the ABS meeting on October 27, 2007. It will be published in the near future.

TRBS 1121 determines which measures intended to achieve the state of the art are required if changes or fundamental changes have been made to an elevator.

The rebuilding catalog for elevators, worked out by the DafA (German Elevator Committee), has been in existence for about 5 years in Germany; it was published in the federal worksheet. The rebuilding catalog is a guideline used to bring existing elevators up to the state of the art during the course of rebuilding projects.

EN 81-80 defines measures to be taken in existing elevators to bring them up to the state of the art (EN 81: Safety rules for the construction and installation of lifts – Existing lifts, Part 80: Rules for the improvement of safety of existing passenger and goods-passenger lifts; English Edition EN 81-80:2003). The objective is to reach, in existing lifts, the safety level prescribed in the EN 81 series of standards. It is applicable to both traction and hydraulic lifts. A rehabilitation plan and schedule can be established using the regulations in EN 81-80.

The basis for technically correct, cost-effective modernization of any given elevator is a comparison of current and target states as described in TRBS 1111, “Hazard assessment and safety technology evaluation” in conjunction with EN 81-80. The hazard assessment can be prepared by the operator; alternately, it may be contracted out to a third party (such as the TÜV – technical inspection service).

In the past, particularly in the course of modernizing lifts, assemblers and operators discussed again and again how the elevator guide rails were to be attached. This was the case especially where a new lift was to be installed in existing hoistways, replacing an old lift. In many instances the attachment points for the new system did not align with the old ones since the new guide rails had a different buckling length or, due to the dimensions of the new lift, the planes for the guide rails no longer matched the old system. Structures, often quite elaborate, were then set up in the hoistway to attach the guide rails. Often a “through-the- wall” concept was used (drilling all the way through the hoistway wall and using threaded rods with nuts at both ends).

The “Elevator Technology” circle at the VdTÜV Conveyance Technology Central Office invited representatives of the elevator and the screw anchors industries to discuss such attachment problems. Moreover, loading and pull-out testing was carried out – in various types of masonry construction – for a number of different attachment concepts and screw anchor designs. The results showed that injection- type screw anchors are suitable for attaching guide rails, provided that the installation instructions provided by the anchor’s manufacturer are followed.

Defined criteria have to be complied with when using injected anchors to secure guide rails. These criteria were published in the “VdTÜV Code of Practice for Fixing Lift Rails in Masonry Shafts; Lifts 104”, August 2006.

That bulletin can be ordered from the VdTÜV website (http://www.vdtuev.de/ publikationen).

The anchoring means used to secure elevator guide rails in a preexisting elevator shaft are subject to the regulations set down in the state building codes and are not a part of the rules or guidelines directly applicable to elevators. It is for this reason that the choice of suitable attachment means is the responsibility of the person installing the system, taking account of the construction regulations in force (model building code, state building codes, lists of building regulations, general building permits or European technical permits). Using anchor rails to make the connection to concrete hoistway walls, particularly in new construction, has become firmly established in recent years although, however, this has been the case almost exclusively in Germany.

Only in those cases where the anchor rails were poorly seated or where the drive units were to be secured were screw anchor systems with the appropriate certificates utilized.

The situation is quite different when anchoring components in existing masonry walls. These hoistways are largely made up of older masonry that often cannot be properly identified. Since, however, building codes permit anchoring components only in unequivocally identified substrates (such as masonry blocks complying with DIN 105-1), elevator installers are faced with the problem of finding an attachment means that also satisfies the building codes. This will always the case, at least wherever the existing guide rail anchor points can no longer be used.

The way in which elevator guide rails are to be attached is not specified in the applicable elevator standards and guidelines, nor are they a component in the type examinations to which elevators are subject. Metal screw anchors used for anchoring in concrete have been included in Building Standards List B, Part 1 (construction products subject to harmonized standards as per the Construction Products Guideline), this on the basis of the ETAG 0001 – European Technical Approval Guideline (parts 1-5). Metal screw anchors used for affi xing in masonry walls have not been included in the building standards lists since there is no approval guideline in force. Thus these anchors, in the spirit of the state building codes, are considered to be non-regulated construction products. Non regulated construction products require, as permission for utilization, either a general construction authority approval or European technical approval or individual approval. Application for individual approval will have to be submitted separately for each building project. Approval notices as mentioned above have, indeed, been issued for various screw anchor systems used in masonry construction. But these limit use, as was mentioned above, to precisely identifi ed substrates, a situation that is hardly ever encountered in practice and particularly in rehabilitation work.

Consequently it is necessary to find a solution for screw anchors in masonry walls that can be used by elevator installers and obviates the need for elaborate individual approval procedures. This solution will have to be technically reliable and safe and be as similar as possible to systems that have already been approved. This solution was worked out in the above-mentioned working circle and was documented in VdTÜV Elevator Bulletin 104, August 2006.

In addition to screw anchor systems certified specifically for the mechanical attachment of insulating materials in façade insulation systems, there are only two screw anchor systems on the German market that have general building authority approval for use in masonry: injection-type screw anchors and plastic sleeve anchors.

The use of plastic sleeve anchors is limited, as per the approval certificate, to attachment to façade substructures (slats or lath, profiles). Injection-type systems, by contrast, are not limited to any specific applications. While the plastic sleeve anchor requires a relatively good masonry block in order to function correctly and be able to accept the maximum recommended or approved loads (for expansion anchors), an injection-type anchor can be used in almost any kind of masonry. The maximum load-bearing value for a screw anchor is, as a rule, determined by the properties of the masonry itself. The damage typically found wherever an injection-type screw anchor fails is that the block or brick in which it is anchored breaks away. Where higherstrength masonry blocks are used, an individual block might be pulled out of the bond.

Contrary to widespread opinion, the injection-type screw anchors are not in fact “glued anchors”. They develop their great load-bearing capacities primarily through positive form fit and expansion inside the cavity. This means that the injected mortar penetrates into the fine cavities and interstices in the rough surfaces of a hole drilled in a solid block and thus interlocks with the material. In perforated blocks, the retaining sleeve ensures that the mortar does not drip away inside the cavity and that plugs are formed inside the cavity. The adhesive action accounts for only very small amount of the load-bearing capacity developed by an injection-type screw anchor.

Injection-type screw anchors, due to the way they work, thus offer the best possible attachment means in masonry, provided that all the components are properly harmonized one with another.

    

The working circle associated with the VdTÜV bulletin quickly arrived at injection- type screw anchors as being a suitable means for attaching elevator guide rails in masonry. The technical advantages are apparent. The elevator manufacturer’s specifications (load per attachment point) serve as the basis for determining the required loading spectrum. These specifications are compared with values established in screw anchor loading tests carried out by screw anchor manufacturers. Long years of experience in fixing injection-type screw anchors in masonry can be drawn upon here. Additionally, series of tests were run on site (in collaboration with representatives of the elevator technology experience exchange circle at the VdTÜV); these tests determined the load-bearing capacities of injection-type screw anchors.

Based on numerous trials and taking into the account the fact that no extensive experience is available with using screw anchors to fix guide rails in masonry, those involved agreed on a pragmatic technical solution with the following features:

- The loads to be transferred at each attachment point are known (elevator manufacturer’s specifications).

- The masonry is dry and at least 24 cm thick (cross bond or English bond).

- Loading tests are to be carried out on site.

- A load application device with widely spaced support points is to be used, so that an individual block or brick can be tested to see if it detaches from the bond.

- The safety margin ν = 5.0.

- Only approved injection-type screw anchors, certified on the basis of the VdTÜV Lifts 104 bulletin, may be used.

- The VdTÜV certificate prescribes the screw anchor system and the equipment required to apply trial loads.

- A retaining sleeve is always to be used since the presence of perforations in masonry blocks can never be excluded.

- Minimum bonding depth for the anchor is 15 cm so that the second row of blocks or bricks can be utilized for load transmission.

- The installing company is responsible for correct use of the anchors (employee training, installation instructions, required equipment, logs).

The test loads may be omitted under certain circumstances. Details will be found in the “VdTÜV Code of Practice for Fixing Lift Rails in Masonry Shafts; Lifts 104”.

    

The screw anchor system required for use as per “VdTÜV Code of Practice for Fixing Lift Rails in Masonry Shafts; Lifts 104” shall be certified by the VdTÜV and comprises, for instance, the following components:

It is necessary for the installation company to observe certain basic rules when dealing with the bulletin’s specifications and with the injection-type screw anchors to ensure that the anchors will be properly installed and that nothing will hinder the subsequent acceptance of the lift.

1. The manufacturer’s installation instructions are to be followed exactly. It is advisable for the workers to familiarize themselves with the system before starting the actual work. This is all the more important since assembly as per the “VdTÜV Code of Practice for Fixing Lift Rails in Masonry Shafts; Lifts 104” may deviate from installation as described in the particular anchor approval certificate (setting depth, length of the retaining sleeve, type of anchor rod or screw). In the case of injection-type screw anchors, proper cleaning of the drilled hole (clearing it of dust and grit) is of major import ance.

2. Only the screw anchors and equipment specified in the certificate may be used.

3. Documentation of assembly has to be complete (condition of the masonry; test loads, including evaluation; screw anchor testing logs; screw anchor system used, together with approval and certificate).

With the current “VdTÜV Code of Practice for Fixing Lift Rails in Masonry Shafts; Lifts 104”, August 2006, the user has a reliable guideline for the attachment of guide rails used with centerguided and center-suspended cars. This represents a practical solution for masonry hoistways when the specifications contained there are adhered to. Given the large number of differing masonry types that might have been used to build any given elevator shaft, injection technology represents the most reliable screw anchor option. The maximum load per anchor point in the substrate is defined during loading tests carried out on location, right in the building itself. The documentation carried out subsequently confirms the proper attachment of the guide rails and ensures the acceptance of the elevator.

Later editions of the bulletin will be published in the future, whenever new findings or new applications become available. Suggestions and pointers in this regard are welcome at all times. In addition, contributions by everyone involved is highly desirable.