Method statements, dilution control and sign-off

0 · What a method statement has to contain

One statement is written for each premises and operation pairing before the visit, and it is short enough to be read on site. If it cannot be read standing up in a stairwell it will not be read at all, and a document nobody reads is a document that protects nobody.

The address, the rooms in scope and the rooms written out of it.
The substrate in each room and what that substrate will take.
The concentrate named on the order, its dilution, and its dwell time.
What is isolated before work starts, by whom, and how it is put back.
Ventilation: which windows and doors are opened, and which must stay shut.
Who is told the work is happening, and who is told when it has finished.
The order of rooms, ending at the way out.

The safety data sheet for whatever is being used travels with the statement. It is the manufacturer's document, not ours, and it is carried rather than summarised, because a summary of a data sheet is the half of it somebody thought was important.

1 · Dilution: measured, decanted, written down

The ratio comes off the works order. The volume comes off the room. Both go on the dilution sheet before anything is poured, together with the time and the initials of whoever poured it, so that a solution standing in a bucket at eleven o'clock can be identified at three.

The container is labelled at the point of decanting, not at the point of use. An unlabelled container is emptied down the drain it came from, however much is in it.

The arithmetic itself is on the front page: the dilution sheet there works out the concentrate, the water and the number of containers from the ratio and the volume, and prints the working so it can be checked rather than trusted.

2 · What goes on the label

Product: As named on the works order and on the data sheet travelling with it, written out rather than abbreviated to initials that mean something different to the next person.
Dilution and time: The ratio as mixed and the clock time it was mixed at. Solutions are made up for the visit and not kept over.
Initials: Of whoever decanted it. One person decants, and that person's initials are the ones on the dilution sheet too.
Hazard information: Carried across from the manufacturer's label. A decanted container with the hazard information left behind on the drum is a container that has lost half of what it needs to say.

3 · Sign-off

The sheet lists the rooms, the operation carried out in each, the time on and the time off site, the drying times given, and anything found and deliberately left in place. It is signed by whoever carried out the work and countersigned on site where there is somebody to countersign — a caretaker, a housing officer, the unit holder. Where there is nobody, that is written on the sheet in those words rather than left as an empty box.