Comparison Rexel Mercury REM820 vs Buro BU-S958

Types of media and materials that the shredder can utilize. Note that, by definition, all such devices are capable of working with paper documents, so paper is not mentioned in this paragraph (some models are generally only compatible with paper and do not allow using other materials). However, shredders with the ability to utilize various additional items are more common — mainly staplers, paper clips, credit cards and/or CDs/DVDs. Here are the features of each of these options:

— Staples. An auxiliary function designed to ensure that stapled materials do not have to be separated before being loaded into the shredder. Allows you to significantly save time when utilizing of such materials, especially in large volumes; also provides a correct operation guarantee in case of accidental contact with the staples.

— Paper clips. Paper clips are removed much easier than staplers and there is no problem with them even with a large amount of documents. Therefore, this function is rather an insurance against getting such a clip into the device along with the document.

— Credit cards. The ability to recycle various plastic cards with magnetic media — credit cards, passes, etc. This feature at least prevents the illegal use of such cards, and with a high security level it allows you to...keep the fact of the existence of a card in secret. Actually, the security level for such utilization is indicated in the generally accepted standard DIN 66399, as like as for paper, and there are seven of them:

• 1 — the card remains intact, its surface is mechanically damaged;
• 2 — the card is cut into pieces with an area of less than 2000 mm²;
• 3 — size of pieces less than 320 mm²;
• 4 — less than 160 mm²;
• 5 — less than 30 mm²;
• 6 — less than 10 mm²;
• 7 — less than 2.5 mm².

— CDs/DVDs. Ability to utilize optical discs, which can also store confidential information. For such media, DIN 66399 also provides 7 security levels:

• 1 — the disk is cut into pieces with an area of less than 2000 mm²;
• 2 — less than 800 mm²;
• 3 — less than 160 mm²
• 4 — less than 30 mm²;
• 5 — less than 10 mm²;
• 6 — less than 5 mm²;
• 7 — less than 0.2 mm².

The largest possible size of the fragments that come out from the shredder after being processed. However, it's told about fragments only in the case of using cross-cutting; for stripe cut models (see “Cut Style”), this item indicates the largest width of the stripes. The size of the fragments is directly related to the security level provided by the shredder; see the relevant paragraph above for details.

The gap size of the shredder is the opening where the utilization materials are placed. This indicator determines the maximum size of the material that the device can handle at one time, without the need to fold or cut the sheet. The common gap size for most office models is 220 – 230 mm — this allows you to easily work with the popular A4 format(sheet width — 210 mm). But for sheet A3, with a width of 297 mm, you will need at least 310 mm gap size.

The speed that processed unit moves through the shredding mechanism during utilization. Accordingly, the higher this indicator, the higher the productivity of the shredder and the more units it is able to shred in a certain time. Knowing the volume of the documents to be shredded, you can easily determine the time required for batch utilization: for example, with a speed of 45 mm/s, one load of standard A4 sheets (length 297 mm) will require 297/45=6.6 s.

However, it should be taken into account that this parameter is usually indicated for paper of a certain density — 80 g/m² (standard office paper) or even 70 g/m², depending on the manufacturer. When working with thicker paper, as well as other materials (see "Shredding Items"), the shredding rate may be significantly lower than stated.

The number of sheets that the shredder is capable of processing at one time — in other words, the largest size of a stack of sheets that can be loaded into the device. Most modern shredders can handle multiple sheets; up to 5 pcs at a time is considered a very limited indicator, up to 10 pcs — a small one, 11 – 15 pcs can be called an average value, 16 – 20 pcs — quite good, and in the most powerful models this figure exceeds 20 pcs.

Note that this parameter is given for paper of a certain grammage (and, accordingly, thickness). At the same time, the East European standard for office paper is a grammage of 80 g/m², and in many European countries thinner paper is used with a grammage of 70 g/m², and it is for it that the capacity of many shredders is indicated. Therefore, if this moment is not specified in the specs, it is best to load the shredder not up to limit values, making a margin of 1 sheet per 8 sheets of capacity — 1 sheet with a stack thickness of up to 8 sheets, 2 sheets with a stack thickness of 8 to 16 sheets, etc. However, other conditions for density may be specified in the user manual.

Also note that the number of sheets per load is determined by manufacturers based on the results of tests under perfect conditions — in the absence of staples on paper, with low humidity,...optimal voltage in the mains, perfect sharpening of knives, etc. In fact, any deviation from these indicators affect some decrease in efficiency.

The duty cycle of the shredder is the maximum time that it can work without interruption.

Limit of operating time is due to the fact that the destruction of documents and other media is associated with quite significant loads on the electric motor and gear. This leads to strong heating, while the breaks allow the hardware of the shredder to cool down. Actually, there are models with the possibility of continuous operation, but they are expensive and not always really necessary; see "Features" for details.

In small shredders for domestic use, the work cycle is often only a few minutes, and among powerful professional devices there are values of half an hour or more. Also note that in some models, shutdown after a full cycle is provided automatically due to overheating protection (see "Features"), however, the presence of such a system does not mean the presence of an automatic shutdown on time — it can only work with a critical increase of temperature.

The minimum break time required by the shredder after a full cycle of work (see above).

A break is required so that the motor and mechanisms of the device can cool down after the intense loads that they are subjected to during operation. Moreover, if the operating time was less than a full cycle, then the break can also be made shorter; however, if the device has worked for more than half of the cycle, for a full assurance it is still worth to take a break for all the time intended for it. Some models may provide other recommendations in this regard — they should be specified in user's manual.

The volume of the waste bin that is filling with shredded materials after passing through the shredder. The larger it is, the less often you will have to empty the basket; at the same time, large containers increase both the weight and dimensions and the cost rate of the device. For comparison: the volume of a standard household bucket is about 10 liters, a shredder with a basket of such a capacity will have dimensions of about 35x30x15 cm and belongs to the entry level in terms of capacity.

The power of the motor that drives the exterminator knives.

Engine specs are selected by manufacturers in such a way that the unit is guaranteed to be able to complete the tasks it's intended to. Therefore, while choosing the shredder this parameter has minor importance, the main attention should be paid to more lifelike specs — the sheets-per-load capacity, the speed of destruction, etc. However, devices of a similar degree of secrecy and price category may differ in power. In such cases, the difference is that a more powerful motor is capable of providing a thicker load stack, a faster shred rate, and/or a longer duty cycle (see above). The cons of these benefits are an increase in cost rate and energy consumption.

Regarding energy consumption, it is also worth noting that the motor power usually more or less corresponds to the total power consumption of the shredder. This data can be useful for some specific calculations — for example, calculating the total power of the load connected to an uninterruptible power supply.