Initial Cost or Total Cost of Ownership: Page 3
RELIABILITY AS A CRITICAL PURCHASE FACTOR
Experience with Mark II/III/VLOM pumps
In general, when lever-arm pumps fail in Africa, the infrastructure is not in place to get parts to the well at all quickly. Then, even if parts can be procured, arranging for repair can consume more time. We are told that the typical unit of measure for time to repair is months.
According to our contacts, 25 - 75 percent of Mark II/III pumps are broken at any given time. The Rural Water Supply Network's Work Plan (January 2009 - December 2011) includes data on the percentage of non-functioning pumps across 21 African nations; on average, 36% of all hand pumps across those nations are not functioning.
The cost of downtime must also be figured into TCO, both in terms of labor time, and in terms in repercussions.
On labor cost: There is no way to provide even a rough estimate downtime costs, but the costs per hour per villager do not have to be very high to make this factor significant.
On repercussions: Citing one incident we heard about: A local micro-economy was hit hard by the failure of their primary source of water due to a broken pump. The costs were quite high because the failure happened in a critical part of the growing season. Even when there is another source of water during the pump's downtime, transporting water from the alternate source, to where it is needed, also imposes significant costs in terms of hours lost.
Reliability of Simple Pump devices
For those who understand modern manufacturing techniques, it is clear that Simple Pump devices would be dramatically more reliable.
The data we have on pump failure is consistent with this expectation. We know of no pump of ours that has outright failed in the first five years. Some parts have been replaced under our five-year warranty under exceptional use -- but even that is a minority of cases. In contrast to this record, some consider the TOTAL effective useful life of a Mark II/III/VLOM to be five years! The Simple Pump has a 50-year useful life.
Over 200 Simple Pumps have been installed in several Canadian solid waste landfills where the Simple Pump is pumping silt-laden garbage water as part of methane recovery operations. These pumps operate 24/7/365 and have been doing so for the past 2-1/2 years with minimal reliability issues. Pump cylinder, drop pipe kits with lift rods, and rod guides used in this application are the same used with Simple Pump hand pumps. The difference is just that each is driven constantly by a 12-volt DC motor.
Over 150 Simple Pumps (model ADA100) have been installed in National Parks and Forests throughout the USA. This model is, officially, "Americans with Disabilities Act compliant". The US Forest Service will not approve any pump for installation into the national park system unless it has a 50-year useful life. Three pumps have experienced problems, externally caused. One was beaten with a baseball bat by an angry teenager, one was shot by a high-powered rifle and one was run over by a pick-up truck. The one run over by the pick-up truck was not operable. The other two continued to function despite the abuse.
Although there is not, yet, extensive systematic field data on Simple Pump reliability, Simple Pump continues to offer its unconditional five-year guarantee on parts, without a single request for replacement to date.
TIME TO MAINTAIN
The cost of villager time to repair a pump should be considered. For Simple Pump, one experienced person, or at most two adults of any stature, can install, or perform once-in-five-years maintenance, in at most two hours. The seals required can fit in a small drawer.
Compare this to any installation or maintenance of Mark II/III/VLOM or AFRIDEV pumps. We have been told by experienced field workers that maintenance of such pumps requires either a heavy lifting rig or manual labor of several individuals that can easily stretch over days. And the equipment needed requires a truck to move!