Specifying CCTV Systems

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There are three main types of specification for CCTV systems.

  1. The proposal presented to a potential customer based on a company’s interpretation of preliminary visits and discussions.
  2. A specification prepared by a customer in which the operating principles and requirements of a system are outlined and the final design left to the installation Company.
  3. A specification prepared by a customer in which the position and performance of every component in a system are clearly defined and specified technically.

There is actually a fourth type of specification. This is where the customer produces a combination of 2 and 3 but with only a layman’s knowledge of CCTV. This is ‘a little knowledge is dangerous’ type of specification.

The first part of this chapter is intended to provide guidance for the first two types of proposal. This is followed by guidance for end users

The size and thickness of a proposal and specification are not necessarily proportional to its usefulness. In addition, the structure of the proposal should be carefully thought out to inform the recipient. The intention should be to provide a reasoned and progressive argument for the system being proposed. Many customers will only have a passing knowledge of CCTV. Therefore, avoid the use of trade jargon in anything other than technical specifications where it is necessary.

Most companies will have their own preferred layout for proposals. The following notes show a structured approach that can be adjusted to fit in with any corporate presentation.

Contractual Considerations

The proposal will form the basis of a binding contract between the installing company and the purchaser. It can be the company’s defence or downfall if there is a dispute. With the best will in the world disputes will happen. In the case of CCTV it is invariably the quality of picture or scenes in view that cause the greatest problems. It is equally important to describe the drawbacks as well as the advantages of the system. This may come across as negative thinking to the salesperson but it can be turned into a positive advantage. Statements of fact can increase the credibility of a company and impress the customer with their ethics. This is especially the case when the competitors have failed to point out the drawbacks.

A common comment from disappointed customers is that, “I employed your Company as an expert, took your advice and now the system does not do what I expected.” This is often followed by refusal to pay the invoice. There have been many cases where this is a smoke screen because they now don’t have the money or are simply being fraudulent. Frequently the complaint is aggravated because it is a very subjective judgement. Such comments as; ‘I can’t read the number plates and see the whole width of the 60-metre entrance.’ ‘I can’t see people directly below the camera.’ The chapter on lenses made the point that many customers expect to see through a camera lens what they see with their own eyes. Therefore, it is important to have laid out exactly what the system will and will not do. The following headings illustrate a structured layout for a proposal.

Contents Of Proposal

The proposal is the main selling document that will be presented to the customer. It is an opportunity to present the company as competent and professional. Besides providing legal protection, it can persuade the customer to accept the proposed system as the best suited to their needs. This is the document that remains after the salesperson has left and is maybe forgotten. Another thought is that many other people will read the document than those that met the salesperson. Therefore, it should be easy to read and set out logically.

Many companies now use word processors with a series of standard paragraphs to construct a presentation. This obviously saves much time and can improve the appearance of a document. However, it can also give the appearance of being produced by a machine and not a person. It is possible to devise a word-processed document that is personalised to each customer and his or her particular needs. For instance, many companies have a standard paragraph describing a pan, tilt, zoom camera mounted on a wall bracket with a 10:1 zoom lens, etc. This can often be about seven or more lines of description within which may be the location and field of view. In a system with sixteen cameras, this paragraph may be repeated sixteen times with just minor changes for each location. This could take up about five or six pages of repetitive information and be very difficult to comprehend. It may look impressive in volume but not in communication. In these and similar cases the camera locations and fields of view could be listed as one part of the proposal, followed by a separate detailed description of the equipment proposed. This would be much easier to read and comprehend.

There should be three main components in a proposal.

  1. The written proposal and specification.
  2. A site drawing showing camera locations and fields of view, the latter being described in more detail within the specification.
  3. A schematic diagram of the system.

Terms Of Reference

This will contain a summary of the invitation to tender and any documentation and drawings provided by the customer.

Site Visits

Details of any site visits made and the degree of information available. Also, state whether further visits will be necessary to finalise site details in the event of a contract being placed. A qualification is especially important here if a tender document includes drawings and a description but site visits are not permitted.

Summary of Brief

This introductory section should describe the brief agreed between the installing company and the customer. This will restate the overall objective for the system and any qualifications to it. The statements could be taken from the checklist suggested in Chapter 20. The purpose of this section is to ensure that both parties understand the reasons for the specification that follows.

There will be instances where the brief has been provided by the customer without prior discussion. It is still important to restate it, as the basis for further comments that will be made in the proposal.

Interpretation of Brief

There will be occasions when further considerations will have become known during design of the system. These could be limitations to desired fields of view or an extra camera needed, etc. These should be noted as an extension or restriction of the original brief. If comments are omitted then the customer can assume that the proposal meets the brief in full. A major trap for the unwary is a document that contains a requirement that the system will provide video recordings suitable for evidential use. In these cases, it should be perfectly acceptable to include a qualification along the following lines.

Use of Video Recordings for Evidential Purposes

It is not possible to state conclusively that all video recordings will be suitable for evidential purposes. It depends upon many factors, mainly the distance the suspect is from the camera and the focal length of the lens. Lighting, quality of the camera, quality of video tape and several other factors all contribute to whether a recording is suitable for evidence. There is also a difference between using a recording for identification and for evidence. The rules of thumb for using video recordings are as follows. (a) To see that it is a ‘person’ rather than an animal or other object requires that the subject should be at least 10% of the height of the screen view. This only infers that it is a person but with no chance of identification. (b) There is a possibility of a subject being identified if they fill 50% of the screen and are familiar to the viewer. (c) To achieve positive identification of an unknown person they need to have their head and shoulders fill the screen.

With the lenses fitted to the proposed system, the person will need to be within thirty to fifty metres to see that it is a person depending on the lens fitted. They will need to be within about ten to twenty metres to stand a chance of identification. Therefore the cameras are generally positioned so that a person is moving towards them and at some point should be of sufficient size on the screen to be of value.

Description of System

This should contain a summary of the complete system in plain English. There is no need at this stage for any technical specification. It should be as brief as possible, simply an outline of the main features. An example could be as follows. The system will consist of eight external monochrome cameras. Five will be fully functional pan, tilt, zoom. The others will be static units showing a fixed field of view. The cameras will be connected back to a central control unit in the gatehouse. The main control will be a multiplexing unit that also contains the control of the pan, tilt, and zoom functions. The multiplexer provides the facility to almost simultaneously record all the cameras in the system. There will be two monochrome monitors, one 17” and one 12”.

This type of description is all that is necessary at this stage. It simply introduces the rest of the more detailed specifications. In the case of a larger, more complex system, it may be necessary to provide sub headings to make a more logical description such as.

Description of System.
- Site system.
- Main controls at site 1.
- Slave controls at site 2.
- Microwave links.

Design Considerations

There can be several different approaches to the final design of a system, with different companies putting forward their own ideas. It is frequently useful to provide an explanation outlining the reasoning behind the solution proposed. This section will put the proposed solution into perspective with other possible competing systems. It also helps to justify the proposal compared to other systems that may be a lot less expensive but do not meet the critical objectives. One example would be where the proposed system includes cable equalising amplifiers because there are large variations in cable runs. Not all companies would consider this factor to be important, and consequently submit a lower price. Explaining the reasons for such features can increase confidence in the proposal and cast doubt on competing submissions.

It is also an opportunity to sell the advantages of certain makes of equipment where these are important to the final performance. For instance, certain makes of camera or video motion detector may include features that are not in other makes.

Schedule Of Cameras

The essential information in this section is the location and field of view for each camera. It may also include details of lighting conditions if existing lighting is to be used. As noted previously it is preferred not to clutter this information with technical detail or jargon. It is still part of describing the system to the customer in terms that everybody will understand. The information would be taken from the schedule of camera locations prepared during the site survey or produced by the customer. A typical specification may be as follows.

Location: Corner bracket 2.5 m high on corner of building 39.
Scene to view: 2 metres either side of entrance ‘A’.
Cable distance to control: 95m
Distance to view: 30m
Width to view: 15m
Lens focal length: 12.5mm
Light levels, below camera 9.3 lux
  "  mid distance 19 lux
  "  furthest distance 5.7 lux
Housing: Weatherproof with heater
Type of camera: Fixed

Any other relevant information should be listed to ensure that there is no room for doubt as to exactly what is being supplied. The details of light levels would be appropriate if existing lighting were to be used; in which case the proposal may specify that the customer provides light to a certain average level. If infrared lighting were to be used then this information would not be required.

If the system includes several types of camera, it is better to simply state the type with a separate list of specifications for each type.

Equipment Specifications

The degree of specification will vary between proposals according to the type of customer. The descriptions of equipment should be specific and informative. Avoid phrases such as ‘high performance, low light camera.’ It is jargon and meaningless in defining a camera. Whether to state the make of each item is a matter of individual preference. There are advantages where the manufacturer is a household name and inspires confidence. On the other hand, with the rapid development in technology it may be considered better to state the specification and select the most appropriate and competitive make when the order is placed. Some examples of typical specifications follow.

This article is an extract from chapter 21 of 'The Principles & Practice of CCTV' which is recognised as the benchmark for CCTV installation in the UK.