CONVENIENT AND ON THE CEILING

Observance of measures of fire safety is necessary for everyone, always and everywhere: at work, at home. And if the companies behind this control is performed by fire supervision bodies, in houses — all this, entirely, entrusted to the tenants.

EXAMPLE OF CALCULATION OF THE SIGNALING

If someone of the readers will need in equipment areas automatic fire alarm system (AUPS) will need to calculate the number of the signaling (SHS) for primocanale unit (PCU) to determine the maximum number of detectors. This, in turn, will eliminate or at least reduce the likelihood of false positives, APP by holding the circuit in the mid range of the “Norm”.

1. The original data. The calculation is based on the example AUPS, consisting of PKP Granit, smoke detectors ДИП212-41M, manual call ИПР513-2 in the amount of 2 PCs., included in flashing mode led with constant and pulsed components of the input current. Electrical parameters are: voltage in V, current in mA, power in mW resistance in ohms.

1.1. The voltage loop USS = 19,5.

1.2. Loop resistance in the “Open”

RRC = 11.

1.3. Loop resistance in the mid range of the “Norm”

RSHS = (4,5-2,5)/2 + 2,5 = 3,5.

1.4. The current one DIP Idip = 0,05.

1.5. The average current of one IPR IIPR=IPOST + 0,5 IUTI = 0,08 + 0,04 =0,12 (this option is checked practically).
2. Determined by the maximum current detection circuit in the “Open EOL resistor”:

IRC = URC/R0SS = 19,5/11 =1,77.

2.1. Determine the current, attributable to smoke from broadcasters:

IDIP = Iloop — I1IPR x 2 = 1,77 — 0,24 = 1,53.

2.2. Define the maximum number of smoke detectors:

n = IDIP/I1DIP = 1,53/0,05 = 30,6 PCs

take n = 30 PCs., the total current I30DIP = 0,05×30 = 1,5.

2.3. Determined by the current detection circuit in mode “Normal”: IENM=USHS/RENM=19,5/3,5 = 5,57.

2.4. Determine the current termination resistor:

IOK = IENM – I30DIP – I2Ypres = 5,57 – 1,5 – 0,24 = 3,83.

2.5. Determine the resistance of the EOL resistor: ROK = URC/IOK= 19,5/3,83 = 5,09.

Choose from the standard range ROK = 5.1, calculate the power of the EOL resistor is not required with three-time reserve capacity is 250 mW.

On a country site or farmstead farmstead house has areas which fall under observation, especially at night: pantry, sheds, Cribs, warehouses. Meanwhile, these buildings also are a fire hazard, especially when they have electricity. It would be nice to supply them with fire alarms.

Fixing “breaking” between the walls of the room rack for the installation of fire detectors

Bracket for fire detectors

Possible layout of the detectors depending on the sizes of rooms:

and — with doors placed in the middle of the wall; b — with doors placed at the side

According to the manual of fire safety (NPB 88-2001*), hull fire detectors should be mounted on the ceiling of the protected premises. Mount them on the walls, although it is allowed, but with great reservations, the implementation of which is often difficult, and sometimes impossible. So this option makes no sense to even consider.

Moreover, with the mounting of the detectors on a wooden suspended ceilings, and no difficulties arise. The difficulty arises when the ceilings are reinforced concrete slabs, such as those in modern buildings and dominated. Drilling numerous fastener holes in them under the fire detector and lead wires is physically difficult, especially at high altitude.

But the output is quite easy and easy. One has only to think and apply innovative solutions that propose to use the readers of the journal “modelist-Konstruktor”.
So, in tight spaces with a width of 1.5 — 2 m for the installation of fire detectors in concrete ceilings it is possible to use wooden slats with a thickness of 15 mm and a width b (the size corresponding to the diameter of the detector). On the ceiling rail fixed “vraspor” between walls, and therefore its length should be 3 — 4 mm larger than the width of the room. Before fixing the rail to Orient a deflection in the direction of the ceiling, and below it were easier “breaking” and didn’t crack when driving — “the setting” angles (edges) rounded with a small radius.

If you want the aesthetic design of the slats can be painted in the color of the ceiling or at some contrast.

Housing detectors perevorachivayutsya to the rail with screws 2,5×12, and connecting wires (usually type TRV 2×0,5) are nailed studs 1,2×15 in increments of 250 — 300 mm.

For rooms, the width of which does not exceed the area of the (perception) of the two detectors, it is possible to apply the self-made brackets to attach them to the walls. The bracket is made from steel sheet of thickness 1.5 — 2 mm. Its width as the slats, must be equal to the diameter of the detector housing. The length of the upper bend (shelves) must exceed the size of 10 mm or more.

For fastening the bracket to the wall will be enough and one hole in the rack. Only to bend the shelf should not be strictly at 90°, and at 2 — 3° less. Then when installing the front bracket the same will press against the wall and the shelf to the ceiling. The bracket can be adjusted to fit more tightly and hammer.

Detectors to the shelf, attach with screws, having previously performed in appropriate threaded holes.

Paint the bracket in different colours: rack — like wall, and the shelf — the color of the ceiling.

SHAMANAEV A., Lyskov, Nizhny Novgorod region.