There are five approved methods or systems of carpet cleaning. At times it is beneficial to use a combination of these methods.
They are listed in order of effectiveness (and use of moisture). Only one method, hot water extraction (HWE), is considered to be restorative, all the other methods are regarding as interim or maintenance cleaning methods to be followed up with HWE at some point (refer: AS/NZS 3733:1995). All of these methods are to be used post pre-vacuuming with a power head vacuum.
1 Absorbent compound cleaning
A highly absorbent granular material (made from corn husks or a synthetic polymer) is soaked in detergent and d-limonene (citrus) solvent and is distributed over the carpet and worked in either manually (usually with a groomer) or for large areas mechanically. After the product has been allowed to dry the granules (which have absorbed the soil) are vacuumed out.
2 Absorbent pad (or bonnet) method
A special preconditioner is sprayed onto the carpet. This is followed by agitation using a low-speed (100rpm) floor buffing machine which has a detachable absorbent pad. The soil attaches to the pad and at regular intervals as the pad ‘loads up’ it is rotated then replaced.
The pads are washed later and reused. It has become common practice to use encapsulation detergents as the preconditioner so that during subsequent maintenance vacuuming dried residual detergents which have encapsulated soil are further removed.
3 Dry foam method (encapsulation)
Originally this method referred to a special type of commercial machine that generated foam, applied it to the carpet and then vacuumed it off all in one process. This was designed for large facility cleaning such as auditoriums and casinos.
Now it is typically where an encapsulation detergent is sprayed on the carpet. This will then turn to foam with agitation (usually with a counter rotating brush machine). Once the foam has dried the product is vacuumed and the encapsulation detergent containing the soil is removed. Any remaining residues are hopefully removed with subsequent maintenance vacuuming.
4 Rotary shampoo method
This was the original carpet cleaning method. Prior to synthetic detergents soap was used to create suds. These were then brushed over the carpet allowed to dry and the flakes of soap containing soil were removed.
Today only non-re-soiling synthetic detergents or preconditioners are used. A low speed floor buffer with a soft carpet shampoo brush is applied to heavily soiled areas (such as traffic lanes, smoke damaged areas etc). The carpet is then extracted using a wet pick-up vacuum or HWE.
5 Hot water extraction (or ‘steam’) cleaning
An appropriate preconditioner is applied to the carpet. A machine (either directly or through a ‘wand’ cleaning tool) sprays hot water onto the surface of the carpet under pressure. This is immediately extracted through the same tool or cleaning head creating a ‘rinsing’ action along the surface of the carpet. Incidentally the term ‘steam’ is a generic term which is no longer popular or accurate. True steam requires high temperatures in excess of 90°C (depending on altitude) and high pressure. While most HWE machines appear to steam at the wand, this is simply mist and nowhere near the temperature of steam (which is just as well as it would damage the very fibres we are trying to clean). Also with the advent of ‘steam mops’ that apply true steam directly to either a textile or hard surface through a microfibre head, it has becoming confusing for consumers.
Types of HWE equipment:
- ‘Walk-behind’ machine
These are historically janitorial pieces of equipment for cleaning carpets in large facilities. They are electric, semi-portable and designed to be used in straight lines (like a lawn mower). Typically, they have a wide (24”) fixed cleaning head and no water heating capability. They compensate for the lack of hot water with agitation from brushes sitting just behind the jets and just in front of the vacuum intake.
- Portable extractors
These are entry level electric machines which can be in endless variations, including high power dual thru to single low power vacuum motor, high pressure to low pressure pump, on-board heating systems, depending on needs and budget.
- Electric van mounts
Essentially these are ‘tweaked’ up versions of a portable enabling longer hoses (15-20m) to be run from the van into the building. They are still limited by the amount of electricity they require.
- Truck mounts
These are independently powered units using petrol or diesel small horse power engines which capture waste heat from the engine with heat exchanger’s and have mechanically driven centrifugal vacuum ‘blowers’. They are able to use hose systems that are 20-40m+ long with the larger units sometimes capable of using 2 ‘wands’ in tandem. They can also be used to provide add on services such as high- pressure tile cleaning.
Important note: Any waste water should be disposed of in accordance with local by-laws.
How do I choose the best products and equipment for my situation?
You are going to have to put some trust in a distributor in order to get the right equipment that suits your requirements and budget. Here are some questions to consider:
- How long has the company been in business and what is their reputation in the industry?
- What qualifications do their sales staff have (how can they advise you if they know as little as you do)?
- What is the reputation of the brands they represent and do those products come with warranties, technical information and meet all compliancy requirements?
- Do they have a trained service network for their equipment?
Also, consider the materials your machine and its components are constructed from. Is it highly durable materials like stainless steel, brass and rotomolded ABS plastic? Does it use materials which will degrade quickly with flexing, wear, chemical exposure and heat? It is false economy to purchase a low quality piece of equipment that will not last as long as a quality one (just like your customers-you get what you pay for!).
This has been a very brief summary of carpet cleaning methods and equipment. But one of the best investments you could make is completing an IICRC certification course and joining your local industry association. Equipment is only as good as the operator.
For more information go to www.carpetcleaners.org.nz
*Paul Pritchard is immediate past president of the Carpet Cleaners Association of New Zealand (CCANZ)