Mass Alerting Systems
April 15, 2008
Several recent events have prompted the relevant authorities to review their methods of communicating with large numbers of people in a relatively small area quickly and reliably. It seems that almost overnight a new industry has sprung up with a wide variety of solutions to offer.
Typically the solutions offered have tended to revolve around the capabilities or knowledge of the proponents, which whilst understandable, do not always provide for the most effective means of tackling a new problem. Fitting square pegs into round holes comes to mind.
Software people believe software-based systems are the ones that will rule the day — however typical of software people, the realities of hardware, networks and the real world tend to be forgotten or neglected if they are considered at all. Hence the profusion of systems utilising what is in reality a convenience toy for children i.e. SMS/Text which I believe should never be considered as a solution for any business solution let alone for emergency communications requirements.
Hardware people tend to believe that everything can be solved by putting up a new network and selling lots and lots of new hardware devices.
The reality is that the best solution, as always, will be driven by careful consideration of the problem, examination of existing resources and judicious use of proven technology.
So what is the problem? Most emergency events occur out of the blue, escalate to a critical state very quickly and then take a lot longer to control and resolve. Long experience has shown that the key to managing the response to disasters and emergency events is communications.
There are two primary communications requirements that arise in such events. The first is the need for responders to be able to communicate with each other and with their command and control facilities. The second is the need to be able to communicate with the people affected by the event.
I am not intending to address the first requirement as that is generally well recognized and certainly the focus of a large amount of resource and deliberation.
The second requirement however, has been less well considered in the past and has become far more important recently with the relatively large number of emergency events that have occurred in the last few years such as campus shootings, extreme weather events, disasters, etc., where information flow has been less than adequate.
Weather events and large scale natural disasters tend to require the ability to communicate with a large population over a very wide area and are reasonably well addressed by existing public communications facilities such as weather radio, broadcast radio and TV. My focus here is more on an ability to provide timely and relevant communications during the course of a localized emergency event in a relatively small area such as a school or college campus.
The nature of such events is that they occur quickly, without warning and if not properly managed can cause considerable chaos, panic and confusion which may also lead to further dangers. I am no expert on the management of crisis situations but I can discuss the communications systems that can assist in the management of such a crisis.
The necessities of such a system are to be able to communicate with a large number of people within the area under threat as quickly as possible, to manage the distribution of information so that it reduces panic in areas less under threat and to keep the information flow going to ensure that it remains relevant to the current and evolving situation.
These requirements immediately rule out any system that is incapable of delivering the information quickly and reliably such as SMS/Text. Such systems might have limited usability for initial alerts in a very small and restricted environment but that very limitation argues for the use of a more suitable technology. Similarly a system that assumes a recipient is in one place — such as in front of a PC — also has limited capability in such situations. It also rules out less discriminative systems that rely solely on an emergency signal that lacks any additional information, such as an audible siren system.
An important consideration is the investment involved in providing systems that may or may not ever be used “in anger” and whether there are other functions that may be used to offset the cost. This also raises the question of whether by using such a system for purposes other than an emergency it may become just part of the background environment and therefore be less effective when required for a real emergency event.
Further consideration needs to be given to what the effect of the use of such a system will be when an emergency situation does arise. Will it cause panic just by its very use?
An appropriate emergency mass alert system must therefore be able to:
1. provide a fast and reliable means of communicating initial alert information
2. deliver information calmly and dispassionately
3. continue to do so regularly and reliably to keep the audience informed
4. be addressable and zone-able so that relevant information can be sent to the right area
5. be useful for other purposes when not used for emergencies without reducing its effectiveness in an emergency
6. utilize a variety of different information delivery mechanisms to ensure as many people as possible have access to the information
7. be scaleable without strain on the network resource
8. be deployed cost effectively
9. be controllable from multiple locations
10. be independent, as much as possible, from reliance on hard-wired power and communications supplies
So what are the technical requirements of such a system and its information devices that would meet these requirements?
1. The system must be wireless as only wireless systems can be installed anywhere regardless of access to power and hard-wired communications cabling.
2. It must be able to handle broadcast information to a very large number of information points without strain on network capacity.
3. It must also have the capability of being addressed by zone or group to allow geographically-relevant information to be disseminated in different areas.
4. It should also be capable of being addressed right down to individual devices.
5. It must be capable of being run off localized power supplies such as solar or back-up batteries in case of mains power failure.
6. It should be suitably constructed according to the environment in which it is located
7. The primary means of disseminating meaningful information should be text-based rather than voice although voice and other audible and visual alerting devices may be used as a means of attracting initial attention
Whilst there are one or two wireless technologies that are being deployed in such systems such as FM sub-carrier via broadcast radio and proprietary radio systems, there is really only one proven technology that is able to deliver on all of the above criteria and which uses open standards technology and readily available equipment from a number of suppliers and that is paging.
Paging is a true broadcast technology which also provides significant individual addressing capability. Its broadcast and grouping capabilities enable any number and combination of receiving devices (terminals) to be addressed extremely quickly and because it can be used for a variety of other uses without affecting its capabilities in an emergency, it is the preferred technology for mass alerting systems.
There are three main components of a mass alerting system:
1. The command and control facility
2. The network infrastructure over which the information is transmitted
3. The terminal devices which receive and display, or are activated by, the alert information
Command & Control
Inevitably the command and control system interface will be computer based and it should be capable of being managed from a number of different locations in case the primary location is compromised by the emergency event itself. Ideally the primary components of the system should be duplicated and geographically separated to allow for both technical failure and compromise. Inevitably there will be trade offs in this between cost and risk.
The software will typically be a messaging system, with as simple a user interface as possible, consisting the devices to be sent the messages, arranged individually and in groups, some pre-canned standard messages and the ability to type in free-form messages. More sophisticated programming functions should be hidden from the normal user to reduce the complication involved with using the system. The system should be capable of handling message input from several locations on site and potentially from offsite as well.
The network may be a dedicated on site system or in some instances a publicly available wide area network may be suitable provided it meets the requirements of timeliness, reliability and addressability. Typically a campus can be covered with a single paging transmitter thus keeping infrastructure costs to a minimum. Depending on the determined risk a secondary hot-back-up transmitter and controller located in a different location than the primary transmitter may be desirable.
The terminal devices are those devices that deliver the information directly to the recipients. In any facility such as a college campus it will be necessary to be able to deploy a variety of different devices for different environments. The most common such terminal devices will be:
Paging controlled LED signs or displays (often called marquees) allow text data to be displayed in an area without the need for every person in that area to be carrying a suitable receiving device. The signs may be constructed in different sizes according to the distance from which they need to be readable and can be constructed for indoor or outdoor installation. LED signs can be used for general information purposes and/or to display the time and date when not being used for emergency purposes but can be programmed to display emergency messages using different colors and sounding audible alerts.
Smaller desktop or wall mounted display devices such as paging data terminals can be installed in locations where a larger LED type display is unsuitable or where it is desirable to provide a more discrete messaging capability. These terminals often provide additional outputs for control of other alerting devices in the area or to activate locks or other security devices.
Portable Terminals (Pagers)
Pagers may be carried by key personnel for discrete messaging and location incident management in the case of an emergency whilst also providing a more general and discrete messaging capability at other times.
A range of capabilities can be added to the system including audible and visual warning devices primarily used to draw attention to the primary terminal devices above. Voice capability can be added using text to voice conversion where it is desirable to add a voice component to the system.
Wireless mass alert systems based on paging are the most suitable for emergency situations as they are able to generate mass alerts over a very wide area almost instantaneously. Follow up information can subsequently be delivered as fast as it becomes available to keep people informed of changes to the alert situation without the risk of overloading the network infrastructure.
Zoning or grouping allows different messages to be sent to different parts of a campus according to the developing situation and direct people to take different actions depending on the situation as it applies in each area.
Whilst primarily acting as a mass messaging facility, such systems can — if desired — also be used to send discrete individual messages to persons with responsibility for large numbers of people e.g. to a lecturer in a lecture hall who can manage the orderly dissemination of the information.
For campuses with restricted budgets paging is also very cost effective with limited infrastructure cost and easy deployment without extensive installation expenditure.
Craig Meldrum is President of WiPath Communications LLC, a manufacturer of wireless data and paging terminal devices and systems used for emergency mass alerting over local area and public paging networks. Contact: firstname.lastname@example.org