Dave
Your spot on with your comment that if you're using these high pH solutions, then the carpet is shot. That's why I support the Woolsafe position that these solutions are used as a last resort problem solver. However, over the years, I've cleaned some really minging wool carpets with Woolsafe Approved solutions and achieved complete satisfaction for all parties. It does take more time though.
The biggest problem that I see, however, is that inexperienced technicians will see or hear of these high risk procedures, whether via word to mouth or reading on internet forums, and start using them on day to day carpet cleaning.
Which now leads me on to Rich's request. You may find some information on Woolsafe . Org, but without doing searches for myself, I can't point you in any specific direction. So I'll try to address some points myself.
Wool likes to be kept at a pH of between pH5.5 to 8. During scouring, most of the lanolin is stripped from the wool, but a little remains. This helps to keep the wool soft and suppleish. High pH and alkalinity will strip this last bit of lanolin. The carpet may look the same, but the fibres become brittle, feel harsher, break more easily and disappear up the customers vacuum, so by wearing out quicker. For some reason, white yarns seem to be more affected by this than some other colours, especially in direct sunlight (sometimes also if never been cleaned).
Alkaline residues can dull the appearance of a fibre, not just wool. When the carpet is wet, it will look fine and feel soft, but not so good when it has dried. An acidic rinse will certainly lessen this effect.
Wool dyes can have a pH as low as pH2. High pH may leave the fibre at, say, pH3 after the first clean, pH4 after the second and so on. The point at which a dye will bleed varies, but as you can see, it could happen at some time
High alkaline residues present a greater risk to people and animals who come into contact with them.
There are bound to be other items I could have added, but the above gives you a good place to start.
By the way, THE best training course I have ever attended was the Woolsafe Course by Julie Roberts of Chemspec Europe. If I were to be King for a day, I would make this course compulsory for all carpet cleaners
Safe and happy cleaning
Ken
