Personal Computers

By Walter R. Stahel
The Product-Life Institute Geneva

This case study was first published in 1989 in German as part of the book:
Stahel, Walter R. (1989) Langlebigkeit und Materialrecycling - Strategien zur Ver­mei­dung von Abfällen im Bereich der Produkte; Vulkan Verlag, Essen; ISBN 3-8027-2815-7. second edition 1992.

A partial English translation was published by the R&D office, U.S. EPA, Washington D.C.

n Electronic office and household appliances, price range: 3,000 to 40,000 DM. Cooperative study with the manufacturing company Siemens-Nixdorf Informationssystems AG, Paderborn and Munich (formerly Siemens AG, division of data and information technology), factory for workstations, Augsburg.

Sections 3.0 and 3.1 (actual manufacturer’s case study) were prepared in cooperation with the manufacturing company mentioned above. For Sections 3.2 and following (product case study) the responsibility lies exclusively with the research group.
(This case study is limited to an analysis and synthesis of the discussions on “Technology”; an optimum primary option for the manufacturer in terms of technology and distribution could not be defined.)

Description of the Product Examined

n PC-AT compatible, product family PCD- ..M/T in desktop and tower models, consisting of a central unit with disk drives, keyboard, and display, without printer, modem, and so on.

Personal computers (PCs) are not the same as data display units (terminals) connected to mainframe computers and without their own computing capacity. PCs (in the beginning also called intelligent terminals) have been around since the early 1980s with their own technical development and market relevance. PC-ATs have been manufactured since the mid 1980s.

A PC system consists of the hardware, the operating system, and the application software. PCs that are compatible with the industry standard all use the portable (single-place) operating system, MS-DOS, made by the Microsoft company. The unit studied can also be operated using the portable multiplace operating systems, UNIX and OS/2. These units are characterized by a high degree of component standardization and durability/long life,

Market Description

The market for personal computers is characterized by rapid technical progress and fast market growth. The market for personal computers is also still far from the saturation point. From the point of view of basic strategy 1, “long-life,” we should distinguish between (interchangeable) units that are compatible with each other (MS-DOS based) and units with their own operating systems.

In the computer trade a distinction can be made between the “system trade” (computer system with application), which is developed directly between the manufacturer and the user, and the “product trade,” which operates via dealers when standardized products are purchased. In the system trade the rental or leasing of complete computer systems is very common. In the product trade this is unknown; that is, the dealer has in most cases neither enough long-term confidence in the product nor presumably the technical capacity for upgrading that would permit fleet management.

Market Volume

The annual sales volume for PCs in (West) Germany is estimated to be about 1 million units, including a broad range of models.

Unit Price Development

The price range for personal computers currently varies, depending on the model, from about 3,000 to 40,000 DM. These prices for powerful units have remained more or less constant, although their performance has increased considerably; that is, the price per performance unit is constantly going down.

Existing Studies in the Field of Personal Computers and Computers

n The Standardization of information and Communication Technology, OECD study in preparation, publication of the results anticipated for 1991; OECD, Paris, Directorate for Science, Technology and Industry.

n Stahel, Walter R. (1989): The Importance of Durability in Operating Systems, Technische Rundschau, 4/1989, Bern.

n Henning, Gernot (1990): The Modular PC Concept; Siemens Magazin COM3-4/90.

n There are some internal studies done by manufacturers, but they are not accessible.

Wear Parts

The electromechanical components — mainly disk drives, fans, and keyboards — are exposed to mechanical wear. The tube is exposed to chemical wear. On the other hand, there are no consumables in the PC, such as in printers (toner, color ribbon).

Effective Life Span

The main components have the following effective life spans:

- Picture tube: 8,000-10,000 hours

- Disk drive (hard disks): 20,000 hours, but as a mechanical component, also in relation to the frequency of switching on and off

- Fan: 30,000 hours

- Keyboard: 107 impacts/key, but also depending on abuse (the keyboard is the actual man-machine interface)

- Housing: essentially unlimited.

Possible Future Technological Advances

Function improvements in the disk drives, central units (CPU), and interfaces are, so to speak, the bread and butter of the PC dealer. In the case of disk drives, every 2 years the access time is halved and there are also new functions such as “disk cache.” These can, in principle, be retrofitted.

On the component level, semiconductor memory instead of hard-disk memory; changeover to optical disks, CD-ROM and W-ROM, and “erasable Mo” memories; increasing disk and memory capacities; expanded interfaces and bus possibilities. These advances can in principle be retrofitted.

1. Actual Status of Current Production and Distribution

Development. Design. and Manufacturing

This appliance has a theoretical life of 25,000 hours or (officially) 5 years (no built-in hour counters). It is designed in a strictly modular fashion and is extremely easy to service and update:

n All the important components such as printed circuit boards are largely standardized in terms of size and power, with standardized connection points; disk drives and (QWERTY) keyboard are 100% standardized (interchangeable).

n PCs can be operated using black and white display, VGA (high-resolution) color display, LCD (liquid crystal) display, and plasma display.

n There are three housings (two desktop and one tower) for the entire product family that can be equipped with various processor assemblies (e.g., with Intel P 286 up to P 80486 and future P).

n For all units there is only one keyboard, which is also compatible with earlier units and programs.

n PCs operate using portable operating systems, which helps to prevent a “pars pro toto” syndrome on the system level; the Siemens BS2000 operating system is also a further example of a rented long-term product, equipped with a 25-year upgrading guarantee from the manufacturer.

The standardization of the housings goes beyond this PC family; the same housings are also used for the workstations.

This unit is durable, largely maintenance-free, and low-cost in service. Most maintenance and updating work can be done by the user himself by means of module replacement. In contrast to the PCs of many competitors, the computers studied satisfy all relevant national and international approval criteria (safety, sweep radiation, ergonomics).

The components are manufactured in Siemens factories (i.e., printed circuits, semiconductors, cables and plugs, keyboard) or are purchased (i.e., picture tubes, microprocessors, disk drives, disks). Quality control takes place on the component, board, and system (PC) levels in relation to function and durability (in the sense of breakdown avoidance) (“burn-in” of system takes 24 hours).

Since these PCs were first manufactured in 1985, materials for the housing parts have been chosen according to the criteria of recyclability (satisfaction of U.S. and Canadian regulations relative to combustibility without environmentally polluting additives). The computer (CPU) has a metal housing, and only one polypropylene plastic is used for the housing parts, except for the key caps, which are made of a different (ABS) plastic because they are inscribed using a laser beam. Recycling of manufacturing waste is already occurring today.

The power consumption of these units depends greatly upon the display units chosen. The computer itself uses on average about 60 W and modern disk drives use 5 W (older ones use 15 W); the display units require from 2 W (LCD displays) to 200 W (color displays).

Distribution (as far as the sales point)

The distribution of PCs is part of the distribution of all communications equipment. Most PCs are rented via the distribution of computer systems or sold by dealers. The warranty is limited to 1 year. Distribution is organized as a separate division from production.

Customer Service

Repair work is done mainly by means of module replacement; the PC manufacturer operates as fleet manager of modules and components. In the case of private customers, the user generally brings the part to the authorized dealer, who makes a module exchange and sends the nonfunctioning module back to the manufacturer’s customer service. The system customers have maintenance agreements available that promise elimination of the problem within 12 to 24 hours.

The manufacturer’s customer service department is organized independently as a separate profit center. The units are built for customer installation and updating. Damaged hard disk drives that are returned to the PC (system) manufacturer are repaired within the scope of an exchange-maintenance agreement with the hard disk drive manufacturers (strategy B3). Damaged floppy disk drives are thrown away (i.e., disposed of as special waste), although the damaged head would be repairable or replaceable. Higher disposal costs would lead to waste avoidance here.

The reader is reminded that responsibility for the text in Sections 3.2 and following (product case study) lies exclusively with the research group.

2. Actual Status of Disposal

The PCs studied have been produced by the manufacturer since 1985, and have not yet reached the end of their useful life, which is over 10 years. A plan exists by which the PCs will be disposed of in an environmentally acceptable way.

Note: This statement does not apply to PCs in general. In many cases there is no “end of pipe” customer service; neither the equipment nor the packaging, consisting of cardboard and styrofoam, is taken back. The authorized dealer is considered the seller and sometimes the expert for maintenance by means of module replacement, but not the disposal agent. Thus it is to be assumed that in the past most PCs (that could not be updated and therefore had short lives) landed at the end of their useful lives in the household trash, at the dump, or in an incinerator.

Production rejects, non-usable series, and units returned to the distributors are, on the other hand, currently already passed on for processing as electronic scrap; each factory uses its own methods.

Since the new Technical Guideline (TA) for Waste went into effect as of October 1, 1990, PCs have to be considered toxic waste. A working group from ZVEI and VDMA has set itself the goal of finding an environmentally acceptable disposal method by the end of 1991.

The annual waste produced by electronic equipment amounts to over 100,000 tons. Electronic scrap contains, in addition to valuable iron and non-ferrous metals, oils, lubricants, batteries, plastics, condensers and gases and fluorescent substances. Computer scrap contributes to electronic scrap at the rate of 7,500 tons per year and this amount is steadily growing. (Quoted from Nature, 9/1990.)

In the area of disposal, market obstacles hinder an application of basic strategy 1, durability/long life, in that agreements between system manufacturers and disposal companies forbid the resale of components for reuse by the disposal company. Whether this obstacle has now lost its importance in practice, as a result of a regulation in the guideline on waste that recycling has to cost more than ten times the dumping costs in order to force disposal companies to develop economically sensible reuse or recycling, cannot be assessed here.

3. Strategies for Waste Prevention

Basic Strategy 1. Durability / Long-Life

A. Long-life products

The PC is a long-life product in terms of design and quality assurance and in terms of the durability of its components.

B. Product-life extension of entire product

All the following strategies are already in place within the company studied for their own needs. The following analyses therefore apply mainly to the German market.

B1. Reuse:

There is a limited market for used PCs. Organized reuse in the sense of “away-grading” exists for computers, which are given away to the former East Germany.

Note: This strategy is successfully employed within the manufacturing company between departments with differing data processing requirements.

B2. Repair:

Repairs are carried Out by means of module replacement, with return of faulty components to the manufacturer.

B3. Reconditioning:

The equipment of modular design is in itself not subject to wear, so that reconditioning of components is usually more sensible (strategy C3); in the case of larger units there is, on the other hand, reconditioning of returns (B3 centrally).

In the analysis of the service sector it is shown that in the field of PCs, computers, and electronic equipment, there are actually reconditioning specialists who mainly work on units after a fire, under contract to the insurer. This measure is economical because of the new-value insurance that is customary in this field.

B4. Technological upgrading:

The unit can be updated as much as desired for the near future.

Note: This strategy is employed within this company at each workplace; that is, it is begun with a low stage of development and upgraded as required.

C. Product-life extension of components

C1. Reuse:

Fleet management of modules (component assemblies) could be carried out by the system manufacturer, combined with strategy B4. The reuse of electronic components is technically scarcely possible, as the connection wires are cut after installation. The reuse of assemblies, combined with the cannibalization of units that are taken back, exists for large pieces of equipment.

C2. Repair:

Printed circuit boards are repaired externally; more costly hard disks and disk drives are sent back to the component manufacturer for repair.

C3. Reconditioning and overhaul:

An exchange/maintenance system exists between the system manufacturer and the component manufacturer for more costly components such as hard disks.

C4. Upgrading:

As technical advances take place on the component level, often with an annual doubling of capacity, this strategy is less sensible than updating entire products (B4).

V. Waste-prevention distribution strategies

V1. Operational leasing and rental:

Exists only for large-scale systems, and not for PCs yet; sometimes fleet management that covers all office equipment (fax machines, copiers, scanners, and PCs) would have to be used in order to reach an economically interesting volume. Short-term rental of portable PCs exists in the United States in all larger cities, airports, and so on.

V2. Shared use:

Exists in some places in practice (e.g., in colleges); would be sensible mainly also for portable PCs.

Basic Strategy 2. Materials Recycling

Problems in materials recycling arise mainly as a result of compound materials, compound parts, special waste, and lack of recycling technologies. From Table 3.A we can see the percentages of materials in these units:

n Compound materials are present mainly in the form of printed circuit boards (epoxy, copper, zinc, lead, and gold) and the picture tubes (heavy metal coatings).

n Compound parts are present in the form of all the electronic components (parts).

n Toxic waste is present, for example, in the form of lithium batteries that are mounted on the circuit boards, as well as the picture tubes; components containing PCBs are no longer used.

n Today’s equipment often does not have any identification marker of materials. This is especially sensible for housing parts, and it should be noted that small parts such as key caps are very difficult to label. Disassembly into fractions of pure materials essentially requires manufacturing information and is limited to the housing components.

n Currently there are only a few separate collection organizations for PCs. The form of disposal of these products is unknown, but it probably occurs together with the household trash via dumping or incineration.

n Lack of recycling technologies: The housing parts made of sheet metal and thermoplastic can be recycled after disassembly. Recycling of other parts would only be possible through close cooperation between the system manufacturers and the disposal companies. A technology for recycling compound materials is in the pilot phase at the company “Interrecycling”; half a dozen other German companies currently have available mechanical methods for recycling compound materials (electronic components, disk drives), that is, separating plastics and metals.

Reasons for Shortened Useful Life

Failure to utilize the possibility of upgrading the equipment because of the lack of knowledge of the owner and/or the dealer.

4. Suggestions for Alternatives to the Actual Status

It would have been a goal of these case studies to define solutions that are technically and commercially conceivable, feasible for a manufacturer, and interesting or at least acceptable to the Siemens-Nixdorf Informationssysteme AG company, taking into account the technical and commercial possibilities for waste prevention in the current situation.

The actual status already largely exhausts the possible “options” that meet the first two conditions. A “primary option” that satisfies all three conditions could not be found for this case study.

Option of Long-Life Products (strategy A)

This case study has shown that the PCs made by this manufacturer already largely possess the characteristics of long-life products (including modular design for hardware and software, component standardization, potential for future upgrading of hardware and operating software).

Option of Product-Life Extension of Entire Product (strategy B)


Existing organizations or new competitors could make available PCs of the first generation (type XT), for example, to schools in the “catch-up” nations in central and eastern Europe or the Third World to a greater extent (in the sense of a fleet operator who disposes of the units at the end of their life in order to avoid environmental pollution in Third World countries).

Fleets of used units:

Incentives can be offered to encourage the return of used units instead of keeping them as spares. These units could then be further commercialized, for example by the dealer, as rental units, without incurring the investment expense of (new product) fleet management.

Keeping as spares (redundancy):

A growing number of second and third PCs will be found in future in private households as “spares” or as practice models for the children. This delayed disposal represents a potential for systematic “away-grading,” but it might, in the event of a technological advance on the system level, cause old equipment to be thrown away in large quantities for obsolescence reasons.

Option of Product-Life Extension of Components (strategy C)

This option is already being exploited by the manufacturer studied in situations where it is feasible.

Option of Intensification of Utilization

Sale of utilization:

The long-term leasing of PCs by fleet operators, in the form of either system manufacturers or independent dealers, would ensure optimum application of the possibility of upgrading the equipment and would encourage cascade utilization in markets with varying degrees of requirements. Fleet operators who are not manufacturers have been working for a long time already in the field of system utilization (including railroads, telecommunications), but to an increasing extent also in the field of investment goods (e.g., aircraft, trucks). Encouragement of these kinds of fleet operators in the field of long-life PCs might become the goal of the economic policy of the state of Baden-Wurttemberg.

Multiple use:

Many PCs sit in offices and homes without being systematically used, just like the cars and campers in front of houses. Multiple use of PCs is conceivable through the following:.

n Companies that rent out portable units, such as are already found in U.S. cities and airports.

n Agencies that make desktop PCs available at PC centers, similar to the photocopiers at copy shops that are found in every city.

Option of materials recycling (basic strategy 2)

It is assumed that currently a significant portion of PC disposal takes place via trash dumping. This percentage will increase in future because of the fact that the market segment with the highest growth rate is small units such as laptops or “electronic notebooks.” The application of the strategy of materials recycling requires the existence of an incentive for the user not to dispose of the old unit in the garbage can. This take-back and disposal system would ensure the disassembly of the units as far as possible into pure materials or mixtures of materials that can be mechanically separated and makes it possible to reuse the materials and safely dispose of the residues.

5 Improvements

Further Measures on the Part of the Manufacturer Toward Low-Waste Products

Manufacturing-based: Reduction of the number of compound parts and compound materials where technically possible.

6 Business Evaluation of the Primary Option

This section relating to the effects of the primary option on the macro and micro economy is missing because no primary option could be defined.

7 Environmental Aspects of the Product PC Model D2M

This section presents an ecological and toxicological evaluation of the materials.

General Assessment

An economic evaluation over the entire life cycle of a product is currently not possible for highly complex technical systems such as PCs. The base data from life-cycle analysis and ecobalance sheets are only known for a few raw materials such as aluminum, steel, wood, polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), and various kinds of cardboard and paper. Since a PC is composed of many more raw materials (see Table 3.A), the pollution during the production of the raw materials and components cannot be quantitatively assessed. In summary it can be said that electronic systems are products whose manufacture is associated with a high degree of environmental pollution and great consumption of resources. This applies both to the manufacture of the raw materials (different plastics, varnishes, resins, metals) and to the manufacture of electronic components such as semiconductors. They are manufactured from pure raw materials in a very clean atmosphere. These purification processes are associated with considerable consumption of chemicals and energy and with emission of contaminants (e.g., solvents). Therefore, this evaluation is limited to an assessment of the disposal of the various components. Materials recycling presupposes that, without a huge technical effort, a product can be separated into materials that are as uniform and pure as possible and that contain low concentrations of foreign substances or contaminants. This condition is satisfied in the case of the PC 2DM only for the most important metals in terms of quantity (copper, aluminum, steel parts) and the packaging materials (cardboard and polystyrene). For a final evaluation we would need additional data on the composition of the various fractions.

Today we have to assume that after the shredding of computers a high percentage of compound parts remain that are difficult to separate out, containing fractions that are relatively severely contaminated with environmentally harmful small metallic particles or dusts. Accordingly, a large percentage of the materials in a PC can be disposed of, but cannot be recycled. Their disposal according to the regulations of the Environmental Protection Legislation is in turn associated with considerable effort.

Metal Fractions

We cannot determine from the available documentation in what chemical form the metallic elements are present. It is assumed that in all probability the metallic form predominates. The recycling of copper and aluminum as the main constituents is unproblematic and has been technologically proven (scrap metal trade) as long as we are referring to relatively massive metal parts that can be easily or magnetically separated. Ceramic materials based on iron oxides cannot be recycled, but they are ecologically harmless. Reservations are expressed relative to zinc, lead, nickel, and tin. It is probably difficult to separate the main metallic components, and these metals are toxicologically and ecologically relevant as contaminants.

Lead and nickel are considered particularly problematic because of the acute and chronic risk to humans if they are inhaled. Of the metals that probably cannot be recycled, zinc, tin, lead, and nickel have the greatest potential for environmental contamination. All in all this mixture of metals has to be considered problematic, insofar as they cannot be recycled or can only be recycled to a low degree.

Organic Substances

Weighing about 5 kg, the packaging materials made of cardboard and expanded polystyrene make up the main fraction of the organic substances. There is a recycling market for used cardboard; the re-use of the foam material, most likely consisting of expanded polystyrene (EPS), has been technologically proven in Germany. These packaging shells made of EPS are already being reprocessed in Germany to make new packaging material.

All the rest can probably not be reused unless individual parts, such as the monitor housing made of PPO or the side panel (probably made of a urea formaldehyde resin), are disassembled before shredding and can be freed of foreign substances.

The shredder waste, that is, the mixture of plastics that results from the shredding process, cannot be separated with a reasonable amount of effort and purified; thus, the recycling of this mixture of plastics to make ecologically sensible arid high-quality new materials is ruled out.

Combustion of this mixture of plastics requires a facility with a comprehensive exhaust gas purification system, as this material probably contains heavy metals and about 10% organically bound chlorine (from PVC). The nitrogen concentration is probably also higher. This mixture cannot be destroyed residue-free in accordance with the requirements of existing regulations. So far there are no suitable facilities for the combustion of mixed plastic wastes; the trash incineration plants with greater exhaust gas purification do not currently have adequate capacities for burning electronic scrap and are also basically not designed for the incineration of plastic waste.


The chemical compositions of the substances (listed under this heading in Table 3.A) are not sufficiently specified for conclusive evaluation. Some of these are extremely problematic types of waste that cannot be recycled even in isolated form. Even the coating of the monitor glass may contain toxic metals, and for the environmentally acceptable disposal of the 270 g of electrolyte in the printed circuits and monitors we would have to carry out further studies and analyses, which are not the subject of this case study.
The obvious primary option for this case study would be the application of strategy Vi, “Sale of utilization,” that is, long-term rental of the equipment (or systems, including application software and printer) by a fleet manager. A discussion of the distribution strategies relative to defining a primary option was not possible within the framework of this case study.

Table 3.A Percentages of materials by weight in product studied, “personal computers”

Table 3.B Technical innovations in the last 10 years

The product studied was only launched in 1985. It is possible to integrate in the product all the technical innovations that have occurred since by means of technological upgrading.