[woodman]

Following on from discusions about residues etc I thought it would be good to get a feel for what we do when faced with a new job of cleaning a carpet.

Do we all really test the ph, if we tested an uncleaned wool carpet some us might get a shock at the reading and be unsure what to do next, so what do you do?

[Dynafoam]

Trevor,

The fact that the vast majority of carpets I clean are repeats has lead me to vote for the second option, with a carpet new to me I always test.

John.

[nordan]

hi i never used a ph gauge .do they cost much and what are you actually looking forwhen useing one.thanks danny

[Mike Halliday]

Ok, i'll ask the question everyones thinking

Why do we need to know the Ph of the carpet? or are we testing the Ph of the dirt on the carpet.

I can understand how knowing the Ph of the soiling is useful, but are we testing the Ph of the carpet so we can return it to its original Ph when we've finished cleaning.

Mike

[nordan]

you can only go down to a ph of eight which is what water is so thats your objective i gess

[Doug Holloway]

Hi guys,

Ther are two basic ways to test pH ,meters which are expensive and only really work on liquids and indicator papers which change colour as the pH changes.
The papers give a rough idea about plus or minus 0.5.

Ph is also a logarithmic scale which means ph6 is 10 times more acidic than pH 7 .pH 5 is 10 times more acidic than pH 6 and 100 times more acidic than than ph7.

It is therefore quite difficult to get meaningful results on carpets and  as has been mentioned by quite a lot of people over the different forums, pH is not the same as alkalinity or acidity.

Confused!

Cheers,

doug

[Ken Wainwright]

Sorry Nordan, you've been misinformed. The carpet pH can (in theory) be anything on the pH scale. Most soil is typically pH5(ish). Distilled water is pH7 Tap water varies around the country, figures I've heard quoted are between Ph6 and pH8.4.

Like John, most of my work is repeat so I know what has gone before. But certainly I'll test unknown and problematic carpets.

Safe and happy cleaning:)
Ken

[nordan]

Hi Ken can you tell me, why test a carpet before cleaning and what levels should the ph be after cleaning. thanks Danny

[neil 47]

a ideal ph for stain resistant nylon fiber would be ph 10 or less . for wool fiber the preconditioner must range between a ph of 4.5 to 8.5
well thats what it recommends in the standard reference guide for professional carpet cleaning given to me by paul pearce for having travelled the futherest to one of his training w/ends for the IICRC
Hope that helps
Neil  

[Dynafoam]

Nordan,

Since Ken is not online:

It can be useful to know the starting pH of a carpet for a number of reasons.

As part of the information gathering stage it can supply detail not visually apparent. It can influence your choice of pre-treatments and in-tank addatives - not only in order to correct an unfavourable status, but because whatever chemical you introduce into the carpet can react with what is already there.

The pH of a stain, in relation to the pH of the surounding carpet can help in identification of the staining agent and thereby assist in treatment selection.

I have come across a number of very dirty carpets where the pH was extreamly high and this enabled me to pre-warn the customer of some of the problems that may be lurking beneath the grime, and an adjustment to be made to the customers' expectations of what to expect as an end result.

There are several other reasons, and the point already mentioned could be expanded to fill several pages, but you get the idea.

John.

[Mike Halliday]

just to be awkward  I'll just mention that carpets don't have a Ph :......until water is introduced to it

and the only information you get from testing the wetted carpet is its Ph. so to say that by knowing this you can judge a chemicals reaction to anything previously left on the carpet ( either by a carpet cleaner or the Mill) is I think a little optimistic

in my opinion the only reason I would test Ph is to help Identify an unknown stain.

also Would'nt any problems be made apparent with the initial test that we all do to check for colour fastness etc,  so belay the need for a Ph check.

Mike

[Ian Gourlay]

Thank goodness for that I thought I was the only one who does not do it.

I will order some ph paper next time I buys some chemicals.

Useful show like fibre test  to make look better than I am.

Not sure how it will alter what I use though.

[Mike Halliday]

Ian, don't worry if you look at the top you'll see there's at least 17 of us who never do it

its a wonder we sleep at night all these carpets we must be ruining

Mike

[Ken Wainwright]

I've missed out on this thread the last few days. I've been pre-occupied with listening to the pratice reports from the Isle of Man TT Races on www.radiott.com Racing starts Saturday so I'll be glued to my computer for the race commentary for the next week or so.

pH Why should we test for it? Contrary to Mikes current position as Devil's Advocate, there can be times when it is soooo important to pre-test for pH. The obvious one is as Mike says, to know what type of stain procedure to take. Another one is pH sensitive fibres from carpets and upholstery which have been previously cleaned by A.N. Other. It isn't unheard of for inexperienced technicians to use a high pH solution in a HWE machine as a single process cleaning system. Sometimes they may even use an aggressive, high pH pre-spray too. Why? 'Cos it's quick and cleans really, really well. They may even use an in-line heater or steamer to boost the cleaning power and pH in use by about 0.5. So for arguments sake, lets say that our pH sensitive fibre has a pH reading of 10. We now know that we need a rinse of pH4.0 to re-balance the situation to prevent any further damage. Why re-balance? The mordaunt (dye stabiliser) present in most topically dyed yarn is acidic. Continuous cleaning with incorrect solutions may, one day, lead to dye migration as the alkaline cleaner gradually "wears away" the mordaunt. It may not happen this time, or next, or the next after that, but it can happen. I've seen it on wool and nylon several times. It actually happened to me too in my early days. A nylon print which had been previously cleaned several times and was OK then failed my pre-clean dye test. I was asked to proceed regardless, but the dyes did bleed and migrate. I was using Prochem's Extraction Pro which I think is about pH 8 to 9, and without TLC. I wasn't very experienced in those days but it seems obvious now that the carpets had been previously abused by other cleaners.

If you've ever attended a training course, you were probably taught to ask questions about the item being cleaned. Why? It's so you can check, amongst other things, for broken seams, excessive foam present, existing shrinkage, delamination from over wetting and the possibility of alkaline residues.

Safe and happy cleaning:)
Ken

PS The easy way to work out what you need to do to balance the pH of any fabric/solution is to subtract the known pH from 14. The answer is then what you need to use.

[Doug Holloway]

Ken,

You and I seem to live in parallel universes!

I as an ex industrial chemist never test for pH as I just do not think it is relevant as is sometimes made out.

Years ago when I was an industrial chemist I went on the Prochem upholstery course with Ron Tilley(1982).
Whilst I found it interesting  , the pH bit left me a bit cold as when I asked pH related questions it was obvious that the understanding was, not surprisingly fairly basic.

If I am worried about potential colour bleed I will pre test with the cleaning solution I am going to use .If there is evidence of colour bleed ,usually reds I will make an asessment as to the how bad its likely to be.
I have always found that if I proceed carefully then colour bleed although evident in the waste water will not cause any appearance problems.

I can honestly say that I have never had a colour bleed complaint on carpets and only once on upholstery many years ago on viscose velour.

I am not trying to be difficult but believe carpet cleaning is basically a practical business which is sometimes hijacked with psuedo science and portrayed as being much more difficult than it is.

Another time years ago I experienced a colour bleed while testing and decided to acid rinse to stabalise.When I tested again the dye bleed was exactly the same!

I have cleaned some carpets every year for the past eons and have never found a carpet which was'nt a bleeder suddenly become one.!

I am only saying what I have found over the past 25 years.

Cheers,

Doug

[Ken Wainwright]

Doug

I have to admit that my real world experiences are as yours. My view with many of the posts I make is that members, especially newbies, benefit from knowledge, and any comments I make will inform them of problems that may happen. It is feasible, for example, that a carpet can be cleaned with an imbalanced pH but it looks fine. A beverage can be spilt and the dye will bleed, but perhaps wouldn't have if the attention to detail had been taken by the technician in the first place. As I stated in my posting above, I have one, just the one, experience of dye bleed in carpet where it could have been avoided if cleaned correctly originally. I've had a couple on upholstery too, but that was for different reasons.

In a nutshell, what I am saying is this. A pH imbalance will not probably cause you any visible problems, but it can. If this happens, it's your fault

Safe and happy cleaning:)
Ken

[Dynafoam]

Doug,

As you would guess from my earlier post I concur with Kens stand point.

When you say that you have repeatedly cleaned a carpet for eons without ever comming across one that suddenly develops bleed problems, this matches my experience. It is the carpet that others have cleaned, without bleed problems, but with the causal damage done that could catch you out.

It's not just a matter of dye bleed, what a bout the carpet that has been yellowed by high alkalinity, but the discolouration is hiding beneath grime. Though you may not be able to correct this past damage, if the client is fore-warned that it may have ocurred, then you are not likely to be the one blamed.

John.

[Doug Holloway]

Hi Guys,

The  problem with pH balance is that we do not know the buffering effect of the chemical used or the water.

This means if you have a ph of 9 which is highly buffered you can acid rinse with 5 and end up with 8.5.
Conversley a lightly buffered ph of 8 acid rinsed with ph 6 could give you 7.

We also do not know the effect of subsequent dirt on pH.
A general consensus is most 'dirt'   has a lowish pH so this would act as a pH balancer if the carpet was left slightly alkaline!

What I am trying to say is that a pH balance would be extremely difficult to achieve and way beyond the boundaries of a pratical carpet cleaning operation.It would require extensive testing and would change as the carpet soiled.

Cheers,

Doug

[Derek]

Doug

You have provided some interesting information that possibly requires a reassessment of what is considered normal.

Perhaps you would be kind enough to give us an insight into your chemical background.

My own experience, other than at school, is pretty basic but I did go for a three day session learning how British Standard testing was carried out...first time I have worked in a laboratory since school.
The testing carried out in these facilities is along the lines already inderstood within the industry with the exception that it is more precise

This makes your posts on the subject all the more interesting

Regards
Derek

[Robert_O]

Very interesting posts

As I understood it, the effect of the buffer in use is to resist change to pH on the addition of either acid or base alkalines.

A buffer tends to keep the pH of a chemical within a certain pH range, even though acids and bases are added.  To achieve a dramatic change in pH, a buffer solution will require many more drops of a strong acid or strong base than will unbuffered water. In effect a stongly buffered alkaline solution used in the cleaning process will be quite difficult to re-balance.

Now what happens when you attempt to rinse a highly buffered alkaline, with a highly buffered Acid?

Like Doug mentioned , how do we determine the buffered nature of any chemicals that are present within the fibres? I have to concede that realistically we are carpet cleaners, not 'rocket scientists', but in my opinion we should always adhere to general good and safe working practices in rinsing out products used and endeavouring to balance the pH as best we are feasably able.

What is the last cycle in a washing machine, 'a rinse'?
What chemistry is used in dye sensitive apparel?
What heat is used in dye sensitive apparel?

Are carpet and upholstery fibres 'so much' different than apparel fabrics and fibres, that we are able to disregard general good practices. To be honest I am unaware of any highly buffered base alkalines within carpet cleaning products, but I am aware of buffering in acidic products. I can only assume that the acid buffering is perhaps more important bringing potentially damaging high alkaline products (on certain fibres)down to the acidic level, which is 'in general' the main state that fibres are dyed into fibres, (with of course some exceptions).


Regards

Robert Olifent