Specification for trailer mounted telescopic Mobile Tower (15m to 40m)
A) General Specification
The Specification defines the characteristics and performance requirements of the Mobile base station
unit to be supplied.
- Manufacture and workmanship will comply with BS 449 or AISC
B) Technical Specification
- The Trailer with tower:
2.1 General Description: The Mast is mounted on trailer as detailed below:
- Weight on axels: weight on axels during transport is compliance to Transport Motor Traffic regulations.
- Height of the trailer with tower: height of the vehicle during transport of tower is compliance to the Maximum height restriction.
- Length of the trailer: length of the vehicle is restricted as much as possible and it is compliance to regulation made by Ministry of Transport.
- Lighting system: complete with adequate reflectors and stop lights.
- Brake system: is based on using air brake system for front axle.
- Max. Mast Height from ground = according to the model.
- Installation time is less than 3 hrs.
- General Description: The Mast is mounted on trailer as detailed below:
- The Supporting structure is a trailer approved for road use. The telescopic mast, which is fixed to the frame, is anchored to the support feet by sets of guy wires and anchor rods.
- Mast climbing facilities: One of the mast faces is provided with step rungs to facilitate the mast climbing.
- Rigging of antennas & feeder: Antenna mounts are provided with the mast to facilitate mounting of both RF or MW antennas. Antenna feeders will run through clicks attached to mast.
- Rigging of antennas & feeder: Antenna mounts are provided with the mast to facilitate mounting of
both RF or MW antennas. Antenna feeders will run through clicks attached to mast.
- The Antenna mounts, in Steel, 3 no cellular antennas (3m pole) & 2 nor MW antennas.
- Design Requirements and Basic of Design
SAFE TOWERS will guarantee the overall safety of the tower.
SAFE TOWERS will submit design calculation report for member design of tower and overall structural stability of the structure, which is signed by a charted structural Engineer.
- SAFE will supply the skeleton to scale, showing the assembly of the structures, the
antenna mounting levels, other detail drawings etc.
- The calculation method to be adopted for tower design will be decided by SAFE TOWERS with the consent of the client.
- All materials will comply with British Standard (hereinafter called BS), Japanese Industrial Standard (hereinafter called JIS) or equivalent standards. The permissible stress of the materials will comply with
BS, standard by Architectural Institute of Japan (hereinafter call AIJ) or equivalent. The standards adopted for all materials will be stated separately.
- General Design Criteria
- Mast will be designed based on BS 8100, TIA/EIA-222-G-2006, IS 802 & IS875 or equivalent international standards.
- The wind loading on the tower and antennas mounted on it will withstand a ground level wind velocity of 140 Km/h and survival speed of 180 Km/h including with height in accordance with latest BSI CP3: Chapter V: Part 2: British Standard (BS)
- Antenna that will be considered when it calculates wind areas will be Six GSM antennas, Two each 600 mm diameter microwave dishes & one 1.2m Ø Microwave plus all the feeders for GSM and MW antennas.
- Allowance will be given to the effective windage area of the following:
- Feeder runway
- Platforms and guard rails
- Ladder and ladder guards
SAFE TOWERS submit the complete data showing the drag factor from various angles of wind on the antenna offered.
- SAFE will supply the following design information relating to the antenna supporting towers to permit an analysis of the design;
- Windage area per meter for feeder runway, feeders, platforms and rails;
- The assumed loading due to the antennas, platforms, ladders, ladder guards, feeder runway and feeders;
- The projected area of the structure over which the pressure is assumed to act and the assumed shielding;
- Tabulation of all thrusts, shears, and slenderness ratios assumed for the various members and any other data necessary for checking the design;
- Bending moment, shear force and thrust diagram of the tower under maximum wind loading conditions where applicable
- Twist or sway of the tower under operational wind velocity will be less than 0.5 Degrees. Also, the verticality of tower will not be deviated from 0.125% of it’s height under negligible wind condition.
SAFE will supply the design information of the maximum deflection of tilt and twist at the top of the tower when subjected to the maximum design wind velocity.
- Maximum allowable slenderness ratio (L/R) for tower members will be:
- Main members (legs) = 150
- Bracing and main horizontals = 200
- Redundant = 240
Where l = effective length of members, r = radius of gyration.
- Mobile tower structure is able to be used in site where allowable bearing capacity of that site is greater than or equal to 150 kN/m2
- Painting and obstruction lights are applied according to ICAO requirements
- Mast is supplied with adequate Lightning Protection System
- Galvanization procedures
- All steelwork and fitting used in the assembly of the tower are be galvanized by the hot dip process after fabrication and before assembly
- Painting or cadmium plating will not be used in any instance as a sole means of protection against corrosion except for repair purposes.
- Obstruction Lighting System:
- Lighting requirements will be in accordance with the Civil Aviation Regulations.
- The lamp unit will be self-contained and maintenance free. Significantly it will be longer life, which will perform maintenance free operation for a minimum of 3 years period.
- Capacitors may be used for energy storage instead of rechargeable batteries.
- The lamp unit will be charged by solar power during day light hours, even in cloudy condition and automatically emit a flashing or steady light through out the night using only the same charge, which will include high intensity, high efficiency solar cells and efficient solid state circuitry.
- The combination of solar charging, rugged constructions and long life components within all climatic conditions (temperature from -20 Co to +50 Co).
- Field proven reliability.
- Whole unit will be light weight, less than 20 Kg and easy to mount.
- Each and every unit will have 3 years fully comprehensive warranty. Any damaged unit except by direct lightning hit or disaster situation, will be replaced immediately free of charge during the warranty period.
- Client’s logo will be printed in every module if required.
- Obstruction Painting
- Towers will be painted according to the International Civil Aviation Organization regulations.
- Three coats of paint will be applied as follows:
- A priming coat of lead oxide type anti-corrosion paint or equivalent.
The priming coat will allow drying up for a minimum period of seventy two hours before application of the next coat.
- An intermediate coat of high quality exterior undercoat.
- A finishing coat of high quality exterior gloss finishing enamel.
- The full paint cover will have a dry film thickness of not less than 0.12 mm.
- All coats will be compatible with one another. They will be supplied by the same manufacturer and will be applied in accordance with the manufacturer’s recommendations.
- All exposed surfaced of the tower will be painted except the upper side of platform decking, the rungs and stiles of ladders, the surfaces which are to met with the antenna panels of their mounting bars and all parts of the earth system.
- The colour of the intermediate coat will be slightly different from that of the finishing coat.
- Lightning Protection and Earthing
- Lightening protection system will consists of Lightening arrestor (Franklin rod), down conductor, Grounding bar, separate grounding rods & connecting cables.
- Lighting discharge rod (Franklin rod), approximately 3.5 meters high one end of the rod will be threaded type.
- Lighting discharge rod will be connected on the tower top. A base will be firmly fixed to the tower top in order to fix the rod (clause 8.2). Facility will be provided to connect the down conductor to the rod base firmly.
- A copper grounding bar with 8 nos of M8 holes (300mm x 50mm x 8mm) will be provided (will mount on ceramic Isolators) in the tower base.
- Separate grounding conductor will be provided to match the full height of the tower. Cable will be 50 sqmm (insulated earth wire).
- Facility will be provided in the tower to clip the down conductor firmly.
- Hydraulic System
- Hydraulically operated system will be provided to operate the tower.
- Hydraulically system is able to be operated with the operating load on the tower
- SAFE TOWERS will submit technical details (Electrical, Mechanical etc.) that will be used with the system.
- Field Experience and Maintenance
- SAFE TOWER will provide the past experience on supply, delivery, installation and maintenance of Mobile towers in detail manner.
- SAFE will provide maintenance works of the mobile tower for five years after the date of delivery of the mobile tower.
- SAFE will provide detailed maintenance agreement for maintenance of the proposed
mobile tower details including types of faults, response time, and time taken to repair.
- SAFE will provide the detail information on spare parts and their availability for time period of 5 years after the date of delivery of the mobile tower.
Lighting is provided for identification of such obstacles in nights and or during reduced visibility conditions.
- The lights will be red in colour and fixed on top the structure.
- If the height of a structure is more than 45 meters above the surrounding ground level, additional lights will be provided at intermediate levels spacing equally in the vertical direction.
- Arrangement of lights will be such that the object is indicated from every angle in azimuth.
- Structures of height less than 45m will be installed with fixed red lights having intensity not less than 10 cd unless otherwise specified by Director - General of Civil Aviation.
- Structures of height 45m or more will be installed with flashing red lights with intensity of not less than 1600 cd. The flash frequency of lights will be between 20 and 60 per minute.
- Lights will come on automatically in reduced visibility conditions.
- Standby power supply will be provided in order to ensure uninterrupted lighting during power failures.