Emergency Warning Siren In Industry

In the large petrochemical complex that I work ,We are having siren for communicating emergency. By different number of pulses of sound we convey type of emergency whether it is fire or toxic gas relaese or air raid.But in times of real emergency , it maynot work because no one will have patience to count number of pulses.The emergency response to different situations is quite diffreent. For fire situation response is to report to complex assembly point & response to toxic gas release is to remain confined in specified enclosed buildings & switch off air intake.
We wish to use either two entirely different tones to differentiate between emergency or use elctronic message boards to flash specific message across all control rooms immediately after presnt siren's wailing sound .
I request professionals to share references from renouned petrochemical companies regarding this .

The Dow Chemical plant in Freeport, Texas, has one of the best systems I have seen. It's the largest chemical plant in the U.S., so it's not surprising. Each plant has a panel board with four switches in the control room, one for gas release, one for general alert, and I forget what the other two are. Each building also has a red phone that is only used for emergency notification.

When an incident occurs, the control room is usually first (or second) to find out. They hit the correct switch, and the air horns in that plant (one city block) give the correct signal (either a solid blast, or a divided blast). That warns contractors in the block to come in to the control room, and warns people in nearby blocks that there is a problem. The operator then dials a number on a regular phone, and it is picked up by industrial security, the fire department, and the medical department. After he describes the problem, the four people decide what the response should be (fire trucks, ambulances, blocking off streets, etc.). The emergency responders are usually on the scene within two minutes. The operator can then make arrangements to evacuate the building, if necessary, or shut the plant down, or repair the problem. Industrial security relays a description of the problem on the red phone system to any nearby blocks that might be affected by it, and the people in charge of those areas decide what their response will be.

There is a second set of air horns along the property line of the chemical plant, and throughout the towns adjacent to the plant. If a problem is deemed serious enough to affect the community, these sirens go off. Citizens are trained to go inside their house, seal it up, and turn on the radio or television.

My current plant has a system based on location. When a problem occurs, the operator pulls a fire alarm (regardless of whether the problem is a fire or not), and a three-digit number is blared in pulses on air horns over the entire plant site. The three digits correspond to a particular location on the plant. The members of the volunteer fire department drive to the fire station, load up in all the emergency vehicles and drive out to the location. This takes about ten minutes. Most of the emergency communications are done over the radio on an emergency channel. Most of the emergencies are ordinary injuries, which means everyone in the fire trucks stands around and waits while the medics load the person on the ambulance and drive away. Most of the plant has no idea what the problem is, unless they have a radio on the emergency channel. Everyone in the affected area has to congregate at the pre-evacuation location to be accounted for, which makes no sense in 90% of the cases.

After reading your postings, I wanted to share my experiences regarding plant and community warning systems. I am an engineer that has designed and deployed computer based emergency warning systems through out the country. I have designed entire infrastructures for chemical stockpile sites to nuclear power reactor sites across the country.

The problem I see with your postings is that it leaves too much room for human error. In the event of a problem the people within the emergency operations centers will be way too busy answering phones and dealing with the emergency to activate the alerting devices correctly and make the "red" phone calls through out the plant/area. Not trying to sell anything here, but many of my customers have found it very useful to let the computer handle all of those tasks in the correct order each and every time while logging all communications for later review during post emergency meetings. That way everything is done correctly, on time, and with full documentation.

Also, using tone blasts are the wrong way to go, the people in the area will have to wait around to hear all the tones before they can react correctly which wastes time when a chemical plum is coming your direction. The use of different tones is the ideal way to pass emergency information quickly. People can quickly and easily determine the tone and react with in seconds, and in high noise areas strobe lights and message reader boards can pass information quickly with out confusion. The only problem is that to obtain multiple warning tones, different siren units will need to be installed. All of these devices can have battery backup so that they will continue to work even if the main power has been disconnected.

In most cases these computer based systems can take over your activation processes with little overhead, or with the use of a network, the supervisors, or others in charge, can have a central point of command to pass messages to the affected people while staying in the safe areas away from the danger zones.

If you would like a more information regarding the services which I can provide related to your systems, please contact me at sirenexpert@hotmail.com.

Thanks!