Redundancy in parcel sortation: How much is actually needed and at what cost?

Given today’s competitive and pressured CEP environment, it’s little wonder that operators are looking for fail-proof systems. For many, this means providing full-system redundancy to cover any possible downtime. But how much redundancy do CEP providers need to build into their sortation systems? It may not be as much as you think. We explain why.

By Peter Ranch Lassen


The role of redundancy in parcel sortation

Redundancy in parcel sortation is the CEP operator’s capability of performing its parcel sortation operations in the event of an error that impacts that performance. The error could be mechanical or operational in nature. In any event, it causes some form of downtime and impacts throughput.

The importance of redundancy to the CEP operator

The ability to continue operations to fulfil sortation obligations and commitment is, of course, critical to CEP operators. Loss of performance can mean loss of reputation and customer loyalty. For public postal houses that have a mandatory obligation to deliver all over the country, seamless performance is particularly crucial, given their close public scrutiny.

The common solution to building in redundancy

It is understandable then that CEP operators are looking to achieve flawless performance in their operations with as little or no tolerance for system downtime.

To accomplish this, many CEP businesses see increasing their sortation equipment as the only sure solution to cover potential system downtime, looking at the issue of redundancy from an equipment point of view only.

But this is a very expensive solution that often outweighs the need. There are, in fact, other less-costly solutions to providing system redundancy.

Do typical points of failure justify large redundancy capabilities?

Before considering those solutions, however, it’s important to note the failure points that call for redundancy in the first place.

Depending on the type of equipment, there are only three single points of failure in sortation:

  • The overhead scanner
  • The sorter controls
  • The mechanical break down of sorter parts

A problem at a single induction in a system with several inductions will not disturb a mission-critical operation severely. Nor will a breakdown of the scanner or sorter controls. A backup scanner can be pushed in on a sliding cart and implemented on the fly. A breakdown in the controls can be remedied with a stop in production of just ten minutes in order to swap a disk before being up and running again.

CEP operators will be forced to come to a standstill only when a mechanical breakage occurs in their sorters. The likelihood of this is extremely low; sorters can run for years without errors if maintained and serviced.

Even if a sorter does break down, capacity is not affected significantly. The sorter’s modular design means only the defective units need to be disabled. They can continue to run until the end of production, when they are removed and repaired. So, if three carts are defective and disabled, the operator loses just three carts’ worth of capacity per hour per revolution.

Similar considerations can be made for the destination points. In well-designed systems there are already alternative sorting destinations in the case of non-availability of single destinations. This type of incident might cause re-circulations that could reduce overall capacity slightly but not severely.

Investing in more sortation equipment to meet these points of failure might not be necessary or worthwhile.

Another perspective: What CEP operators should also consider

Before devoting more capital on further equipment, it may be better for CEP operators to seek to understand their need for redundancy at a level where they are are able to make informed decisions.

CEP operators could ask themselves how often they actually experience a need for redundancy in their operations and have they evaluated the consequences of their system failures?

Does the occurrence really justify a significant investment of capital in a second system or could they survive and perform reasonably without overdoing it? Is one single point of failure acceptable?

Can they live with a breakdown of two hours? If redundancy is required, how high a percentage of redundancy is then needed? Or can the operator, for example, overcome the situation with an alternative solution, i.e. a manual floor operation to finalise the remaining production?

By examining their need for redundancy more closely and from an overall perspective of what redundancy actually means in their operations, they may find they don’t need redundancy at a worst case scenario level.

Redirection within their own networks

CEP operators could consider utilising their networks as a redundancy measure, for example.

If they have a large network, operators can redirect parcels to a nearby sorting centre when a situation occurs or make other terminals in their network overperform for a short period while repair work can be carried out. Redirecting to other locations and absorbing the extra transportation costs can be more acceptable than investing in redundancy technology.

The ability to use networks as an alternative solution will of course depend on how flexible and robust that network is.

Using the floor and manual labour

Adding an extra section to the building or dedicating floor space for performing manual sorting can also be cheaper than investing in more equipment. It could be that 70 percent redundancy in a plant is acceptable in the event of a breakdown and the remainder of production is performed by hand.

However, this option may depend on how automated the hub is. If it automated its operations some time ago and has lost the manual skills required, this may not be an option. If the hub has freshly introduced automation, it will be less of a problem to organise work on the floor in the event of a system disruption. The cost of labour in the local market will also be a driving factor for CEP operators considering their redundancy options if resources need to be hired in.


CEP operators often have a different perception of the level of redundancy needed in their systems compared to what is in fact needed. The best way to determine just how much should be built in requires a careful consideration of whether their operations are mission critical, the consequences of system failure and the likelihood of system failure occurring.

From this basis, CEP companies are better placed to decide whether a partial redundancy solution is enough. It’s a matter of determining objectively the need for redundancy and the most cost-effective strategy to overcome it.

Subscribe to our newsletter