4.5 Instructions and Procedures

Operating instructions and procedures are written so that a process, a plant, or a piece of equipment can be operated unhesitatingly, accurately, and economically. These documents present a series of steps followed in a regular, definite order to achieve a specified result. The goal is to enable a user to carry out an action with which he or she might not be familiar. Procedures and instructions save the time, transfer expertise, ensure consistency, and prevent errors and accidents. They may amount to a single sheet for assembling a table, a lengthy manual of operating routines for a nuclear reactor, or a computer manual full of routines for using an operating system like UNIX or DOS.

They are generally organized as follows:

Purpose and scope. States what the procedure accomplishes and the extent of its application.

Preliminary requirements. Identifies any items such as documents, personnel, special tools, approvals, field preparations needed to perform the procedure.

Warnings. Includes any dangerous aspects in performing the procedure.

Steps. Gives a step-by-step series of actions to be carried out in completing the procedure.

The style of those texts must therefore be:

accurate: the exact meaning of each instruction must be clear;

comprehensible: each instruction must be manageable, not too involved or overloaded with information, not blurred by explanation and description;

adequate: there must be enough information to permit operation, or at least there must be exit branches specifying where additional information may be found;

complete: all feedback loops and branches must be specified;

in sequence: the steps must be in proper order;

safe: warnings must be prominent and well-placed;

acceptable: the tone must help gain the response desired; it must not produce resentment or hostility.

To meet these requirements, it is necessary to go beyond consideration of style. We must consider the selection, arrangement and physical presentation of information; we must have in mind constantly the frames of reference of the receivers, their levels of expertise, their past training (if any), and the contexts in which the instructions have to be used.

An important aspect of procedures is their extensive use of chunking and step-syntax. Chunking is the sorting of parallel elements into prose sentences or elements that are easily located on the page. Step-syntax is the use of special imperative sentences to identify the action in each step of the procedure. A typical imperative begins with the action first, as follows:

Cut the end of the cable, as shown in Figure 2-1, removing any sharp wire ends that protrude from the jacket.

In such piece of writing as an instruction or procedure the danger of a vague word like should, for instance, stands out obviously. Each use of it in any instructions should be scrutinized closely, as it may reduce to a comment an item intended as an instruction. If it is necessary for a reactor to be warmed for two hours before use, to write the reactor should be warmed will not be adequate. You will have no grounds for complaint if the warming is omitted, as you have used an optional form: you must write warm the reactor (an imperative).

The word will can similarly reduce an instruction to an observation. The filter will be changed every six hours simply states a fact: noone is instructed to change the filter. To make this an instruction, you must use an expression such as change the filter.

Another vague word is check. Again, you will have inadequate grounds for complaint if nothing happens in response to the instruction check that the drain valve to the top of the column is closed. Is the operator simply to report the state in which he or she finds the valve? If you want the valve closed, you must write ensure that the drain valve to the top of the column is closed.

Other dangerous words are:

select: select first gear: does this mean there is a choice of which gear is to be used first?

locate: locate the retaining knob on the baseplate: does this mean ‘find’ or ‘connect’?

replace: replace the pin that is damaged: does this mean ‘put it back’ or ‘fit a new one’?

The other important thing in instructions and procedures is the use of terms. To be safe, it is necessary to define service activities and process activities clearly. Each word or phrase in an instruction sheet must be considered in relation to the readers’ background knowledge. Will they understand expressions such as:

Slacken the cheesehead retaining screw. Remove the camerated segment. Examine the wheel disc for signs of fretting. Slide the guideplate right home. Pull smartly upwards.

The first three examples use specialist jargon; will all readers understand them? If so, they can be used by all means. If not, they must be either explained or avoided altogether.

Constant attention to the readers’ frames of reference is vital. Do they know what is meant by connect up the supply tank and the liquid gas vaporizer in the usual way? Do they have in mind the same ranges as you have when they read your instruction to ensure there is little or no pressure in the reactor or set the pressure in the main to about 40 p.s.i.?

And will it be clear who is to act in each instruction? Clear indication of the agent, if it is necessary to specify one, will depend on two things: the format of the complete set of instructions, and the style.