Below I will describe some techniques and recommendations that must be had to make an audio evacuation design.
How do you know if the design process being implemented is appropriate for the audio evacuation project? It is a big question, and is that when it comes to saving lives, the designer should do everything possible not to make mistakes.
Before taking plans, start designing, locating loudspeakers, and quantifying the value of the project, the first task the designer must do is sit down with the client or his or her representatives who are in charge of building safety, and do not talk about the private security, I speak of the committee of people who ensure that the safety standards in the workplace are fulfilled (in Colombia they are known as SG-SST). This group of people is responsible for designing evacuation plans in case of incidents or accidents that could endanger the lives of people occupying the building.
But do not worry if at the time of design this group of people has not been hired, it is normal, that is why the designer architect is always available, since he had to design the building or space according to the current standards of evacuation. He can indicate evacuation routes, spaces with their demographic density (how many people per square meter), critical spaces, private spaces (they have restricted access) and most importantly, isolated spaces where they are not known to be going outside of this. I always use the same joke, but in the undead movies there is always one in the room that no one expected, he died without knowing that his life was in danger.
Since you know the housing concept of the space to be designed, start by performing a preliminary speaker design. Remember that the main function of the speaker is to reproduce the pre-recorded messages, so its design must be intelligible (must be understood), homogeneous (same sound pressure in all similar spaces) and efficient (lowest possible cost, not cheapest). If possible, try simulations of the selected speakers, ideally a design in 3D, but if you can not, there are 2D software that deliver very good predictions.
You already know which speaker to use and where to locate it, unlike a conventional system of calls where you use a pair of cables for all the loudspeakers and a large distributor audio amplifier, in audio evacuation you have to zonify the spaces according to the evacuation plan. And that these are independent, for example, generally the areas are divided into: evacuation ladders, evacuation corridors, work areas, common areas, private spaces.
Some of the zones will only sound according to the emergency plan, others may never ring and others may be used for calls, environmental music, and can even be used to amplify the audio of conference rooms. Do not forget that for evacuation is essential that the system does not fail, what happens if you cut a cable? What happens if a circuit is lost? The most common is to have two circuits per zone, commonly called A and B, and the cable used for this must be fire retardant or its channeling should be designed so that the fire affects slowly, the cost of the cable increases and much.
Having defined speakers, zones and circuits is important to define the amplifiers and the type of programming level they have, since to avoid operating failures due to lack of state of these, you must use amplifiers that at least deliver a fault signal And on and / or off state. If they are controllable remotely it would be much better. Remember that saving lives in the design goal, and if you do not know the state of power, we do not know for sure if the system may or may not save lives.
Since you already have the whole distribution stage, now let's focus on the evacuation procedure, what messages, how many messages, who will take over the command in case of evacuation. These are the questions that will define the audio inputs of the evacuation system. The priority of each entry will depend on the action plan in the evacuation system. From the most important to the least important are generally defined as:
1 Priority: microphone located in control or control station
2 Priority: microphones located in accesses and elevators for firemen
3 Priority: pre-recorded evacuation messages
4 Priority: pre-recorded alarm messages
5 Priority: other operational microphones
6 Priority: Standardization messages
The evacuation audio system can not operate on its own, and it must be automated to interact with other building subsystems such as fault detection and access control. It is necessary to define with the company in charge of the design of alarms and the client how will be the protocol of communication between the systems and how will the interaction of them. Who will activate and deactivate both systems and what will be the hierarchy between them. Basically you have to define the leader, which for obvious reasons will be the building alarm detection system or the building management system.
Since it basically has the characteristics of the design, it is easier to select the brain or audio driver that can fulfill all the features necessary to fulfill the difficult task of saving lives. Remember that these can be certified or not, they can be complete solutions or a tailor made solution, no matter what type of solution you choose, as long as the selection is technically based on the minimum characteristics required for this work such as redundancy, Faults, fault circuit switching, among others.
To finish the design, request that a companion of the company or an external company revise the design and try to find errors, remember that in an emergency our brain is less analytical and tends to prevail the survival instinct.
This is a short, very short summary of how to make audio evacuation designs, many issues were not addressed in this article and possibly there are many doubts, there are several organizations that give excellent design courses, but if you have timely doubts I possibly can solve, you can write to me at email@example.com
- Know who are responsible for the security of the building or designer architect
- Know the spaces very well.
- Selecting and Placing Speakers
- Select zones and their operation.
- Select the wiring and how this will be installed
- Select amplifiers suitable for audio evacuation.
- Selecting audio inputs
- Selection of control signal inputs
- Controller selection
- Design auditor