#Pelco
QUESTIONS – ANSWERS
«Hello! I am designing a fire alarm system for a data center, and the customer wants the system to issue a fire message for each equipment rack separately. Point smoke detectors are not sensitive enough to detect a fire early, and installing one aspirating detector per rack is too expensive. Tell me, are there any solutions to this problem? – Andrey KOLESNIKOV, Moscow»
Roman POLESHCHUK, Head of Fire Alarm Systems, Bosch Security Systems, answers the reader's question.
Hello, Andrey! Indeed, fire alarm systems for data centers must respond very quickly to fires in equipment cabinets.
After all, in addition to the loss of expensive equipment, a fire also causes damage associated with the downtime of the enterprise and the loss of very important data, which can become very critical.
And your customer can be understood in his requirement to localize the fire down to the cabinet.
In your case, it is best to use aspirating detectors, and set to maximum sensitivity to ensure the earliest response to a fire.
There are aspirating detectors with a fire localization function with an accuracy of up to the air intake opening.
Their operating principle is based on determining the time of smoke delivery from the air intake opening to the detection module.
This function allows you to reduce the number of aspirating detectors used to monitor cabinets with equipment.
It also makes sense to use aspiration detectors connected directly to the addressable analog alarm loop.
This allows you to avoid using matching modules (addressable expanders), which significantly reduces the cost of the system, simplifies installation, reduces the load on the addressable loop and increases the information content due to the increased number of notifications transmitted to the fire panel.
«The number of parking spaces in our business center is significantly less than the number of cars of tenant companies that have passes for entry.
In addition, the rental companies order one-time passes for the entry of their visitors' cars, which are practically not recorded, and some visitors generally drive «in the tail» of the car in front.
In connection with this, various conflict situations occur in the parking lot.
Please tell me, is there a ready-made solution for systematizing the work of a parking lot, primarily for distributing parking spaces between different tenants and their visitors? — Alexander Biryukov, Yekaterinburg»
The reader's question is answered by Evgeny KIN, head of the representative office of Nedap N.V. Security Management in Russia
Indeed, many organizations experience problems due to the insufficient number of parking spaces near office buildings.
Modern security management systems can help solve them, the software of which provides the ability to distribute available parking spaces between different tenants and their visitors in an organized manner.
For example, systems are offered on the market that distribute people into groups, and define the parking as one zone.
The accounting software manager calculates the number of entries into the zone for each group and ensures optimal occupancy of available parking spaces.
Below is an example.
Let's assume that one parking lot is shared between two organizations.
Each organization has 15 employees, but the parking lot only has 15 parking spaces.
The distribution can be as follows:
Zone: max. 15 parking spaces
Group A: max. 8 people/cars
Group B: max. 12 people/cars
Thus, by defining zones and groups, the system makes sure that the tenant cannot use more parking spaces than he is allowed.
The difficulty in counting visitors is that they usually do not have an electronic pass that will allow them to enter the parking lot.
This issue can be resolved by creating a special group for visitors.
A security guard or administrator can allow a visitor to enter and determine which group he will belong to.
But this can lead to a failure in the calculations, since the visitor is granted the right to enter, despite the fact that he is not a member of the system.
Defining a visitor into a special group will help avoid any disruptions.
Entry will be counted against such a group and will not be mixed with other groups or zones.
It is very difficult to avoid a situation where sometimes one car is «in the tail» of another car in front of the barrier.
After all, the second car can cross the barrier unaccounted for, which will disrupt the counting process.
In such a case, the automatic reset function of the system values to the original ones may be useful.
Resetting the values will ensure that a new counting starts from the current moment to avoid errors associated with unauthorized movements.
«IP video surveillance has become very widespread.
Are there any restrictions on the use of IP cameras outdoors? I heard that there are some peculiarities and technological problems? — Mikhail Sklyar, Vologda»
The reader's question is answered by Pelco manager Oleg NIKULIN
Indeed, IP video is already very widespread.
And indeed, there are a number of technological problems that must be remembered when designing an outdoor IP video system.
Firstly, megapixel cameras, as a rule, use a CMOS matrix as a photon receiver.
Unlike a conventional analog camera with a CCD matrix, megapixel cameras are very sensitive to temperature changes. As the temperature increases (and the camera in the casing, being in the sun, heats up to 50-60 degrees C), the focus «runs away» and, as a result, the picture blurs.
Therefore, an outdoor IP camera must have autofocus.
It is not always possible to solve this issue using an autofocus lens, since special very expensive optics are used for megapixel cameras.
A standard $25 lens cannot be used on a megapixel camera. It will kill all its megapixels.
The second point is connected with the same CMOS matrix: the minimum sensitivity of a classic analog camera is an order of magnitude better than the minimum sensitivity of a modern IP camera. This is a technological problem.
As a solution, we can recommend installing only IP cameras with the «day-night» function outdoors and, when choosing a vendor, carefully look at such a parameter as minimum sensitivity.
Many aspects are related to power supply and signal transmission.
The maximum distance of an IP camera from a switch is 100 m. 100 m outdoors is extremely little, which means that you will have to install special outdoor cabinets to accommodate intermediate switches or use converters to transmit Ethernet over fiber optics.
This is additional money and complications.
For example, when equipping the perimeter, it is still more profitable to use analog cameras with fiber optic converters and encoders installed at the other end of the line, i.e. in a warm room.
By the way, the capabilities of megapixels in application to security television, in my opinion, are greatly exaggerated.
Yes, there are tasks where megapixels are necessary — airport halls, train stations, large areas, adjacent territory.
But in most cases (entrance to the building, corridor, office premises and rooms) one megapixel is enough for effective surveillance.
Installing 2- and 3-megapixel cameras is like shooting sparrows with a cannon and wasting disk space, i.e. reducing the archive depth.
Thus, IP video contains many more different aspects than analog video and, as a result, requires much more in-depth knowledge from designers and installers.