CW Milestone – Part 9 - Generator installation & commissioning

Although the trend now a days is to avoid diesel generator on new telecom sites and discovering other energy resources e.g. solar,  as off-grid powers supplies. However due to space restrictions and big CAPEX (capital expenditure i.e. initial investment) as compared to diesel generator, still makes the most favorable option as off-grid source of powers. Installation of diesel generator along with its fuel tank, are considered under the domain of CW in telecom projects. Installation of generator set is important because without it, site cannot be declared as RFI (Ready for Installation).

Therefore following should be taken care of when installing diesel genset (generator set) and its fuel tank and specially following points should be taken care of.

1. The genset and fuel tank would be installed on the top slab as per approved layout.
2. At the same time ATS panel is also installed on the cable ladder along with all connections.
3. The genset is connected to the ATS panel and its alarm cable is also routed to the same panel.
4. The fuel tank and genset are also connected to the main grounding system

CW Milestone – Part 8 - Tower Erection (And Recommended Torque Values)

Following must be ensured in installing different tower accessories:



Tower Erection In Progress



Lightening arrestor to be installed on legs adjacent to ones where BTS equipment is placed.

Antenna and dish mounts must be installed at heights and angles depicted in technical documents.

Fall arrest must be properly installed.

Rest platforms must be installed at the specified heights.

All the tower bolts must conform to the allowable torque limits.



Torque Wrenches



Ensure that torque wrench is being calibrated before use.

Torque test would be applied after finishing of tower erection by subcon in front of CW Engineer to ensure the tightening of tower nut & bolts up to the standards.

Tower Nut & Bolt Essentials

       It is to be ensures by a Civil Engineer by client or at least by major vendor to check the nuts and bolts supplied by tower manufacturer are of good quality and of high tensile strength. There are two possibilities for tower supplies. One is that tower is supplied by a company which manufacture its own tower. That is they have their in-house designers, set standards and manufacturing. Such supplies are more reliable and have good standards of quality. 2^nd scenario is that, which is becoming common now a days that a client or major vendor get their tower designed by a trusted designer, according to their own specific needs. And then they bid from local manufacturer for manufacturing of designed towers and come in agreement to those who have lowest rates. Later supply models need to be scrutinized carefully by occasional detailed quality audits, quality inspection of material before dispatch and at arrival on site.  

ISO grade 5.8 and 8.8 grades are normally recommended by designer. The number prior to the decimal point is approximately 1/100 of the nominal minimum tensile strength of the bolt in N/mm2 or MPa.The number following the first decimal point is more or less the ratio between the minimum yield stress and the minimum tensile strength, times ten. Grade 8.8 nuts and bolts are more durable and reliable.

Whatever the case is, it is highly recommended to use same grade of nuts for whole tower structure. Below are some common toque values used in tower telecom erections. Note: These values are just for a guide only if torque values recommended by designer or manufacturer are different then prefer those.

Bolt Dia.	ISO Grade	Minimum Torque		Recommended  Torque		ISO Grade	Recommended Torque
		(N-m)	(lb-ft)	(N-m)	(lb-ft)		(N-m)	(lb-ft)
M10	5.8	15	11.1	22	16.2	8.8	31	22.9
M12	5.8	40	29.5	55	40.6	8.8	54	39.8
M16	5.8	78	57.5	110	81.1	8.8	130	95.9
M20	5.8	120	88.5	170	125.4	8.8	255	188.1
M22	5.8	145	106.9	206	151.9	8.8
M24	5.8	150	110.6	200	147.5	8.8	440	324.5
M36						8.8	1550	1143.2

After tower erection, all the necessary tower accessories like cable ladder, lightening arrestor, fall arrest system, tower lights and mounts (both antenna & dish mounts) are installed as per technical documents.
Below are some more hotographs of tower erection in progress

CW Milestone – Part 7 - Boundary wall

Boundary wall is provided on a greenfield telecom site for safety purposes. Sometimes instead of boundary wall a steel fence can also be provided based upon agreement at the time of bidding or on a later stage. Steel fence will be discussed at a later stage. At some places it is more convenient to use concrete blocks. Same guidelines can be helpful with appropriate modifications.

Rough face of bricck boundary wall

A Typical boundary wall drawing on a telecom site

The backfilling of the compound would be done in layers up to the required level. Approved backfill material would be used to get the desired compaction.

Construction of boundary wall is then made on the edges of leased area. Any of the three options like, reinforced brickwork wall, pre-cast boundary wall and galvanized fence can be adopted. Barbed wire is then installed on the wall for security purposes using turn-buckles to tighten it. Meanwhile the gate (hot dip galvanized) is also installed on the entrance to site.

During the construction of reinforced brickwork boundary wall following points should be checked.

• A-Class bricks would be used.

• Alignment of area should be correct as per drawings.

• Brick Fog portion should be in the upward direction.

• Bricks should be properly soaked before application of mortar.

• Verticality should be checked after placement of every three layers of bricks.

• Ask mason to tie a string around the first stake and loop it around the rest of them until bricks are being laid to the last one, where the string is being tied off. This helps to keep the boundary wall straight and keeps the bricks at same level.

CW Milestones Part-6 - Backfilling and top slab pouring

Once the proper curing of the foundation pad and columns has been achieved, backfilling of excavated area has to be started. At instances (as per project demand and mentioned in DEDs) the backfilling is also required for whole site up to a certain level. This is normally required, when EGL at site is lower than its surrounding. Or if there is risk of flooding during some part of year due to excessive rains etc.

In some rollout projects where BTS and Generator pads are under tower, the top slab or pad is supported by columns and is cast monolithically on beams connecting all the columns. And in some projects, there is separate pad for BTS/Equipment and Generator/Fuel Tank. In later case the, the supporting wall (either concrete or bricks) for pads, has to be raised before backfilling.

CW Milestones Part-5 – Concrete pouring of foundation pad and columns for tower (Greenfield Site)

Once the proper layout, excavation and lean concreting (CW Milestone Part -4) has been done, it comes now the time for steel fixing. The steel for pad/s and columns is then cut and bent according to bar bending schedule. In the meanwhile the size of foundation is marked over the lean layer. The steel for foundation is then fastened with the help of binding wires and placed over spacers to give specified cover in both horizontal and vertical directions. The main reinforcement for columns is also fastened which is extending from top right into the foundation re-bars. 

Workers tying steel ribs for foundation columns



CW Milestones Part-4 – Excavation, Layout and Lean concrete

When site is being kicked –off, the site becomes the responsibility of Civil Works. And the period between Kick-off and RFI becomes very crucial for maintaining overall project speed because during this time only one department (i.e. Civil Works) is working on site. For the telecom rollout projects,  this period normally becomes among major bottlenecks, if not handled or planned properly. And the sales and management team has to be thoroughly worked out this period and need to identify for any manageable (contract negotiation/finalization of subcontractors, Sub-con preparedness and their relative brainstorming and trainings in order to be synchronized with targets etc.)  and unmanageable constraints (like offshore supplies of masts or generators etc., shortage of construction material etc in market), before finalizing and sharing targets and deadlines with customers.

The first thing after kick-off a civil subcontractor has to do is to mark boundaries of site, and clear or demolish (if required) the things within parameters.

CW Milestones Part-3 – Site Kick off

After Work Package approval, a formal hand over meeting is being arranged by Site Acquisition department, called site kick-off. This is the first and most important step which counts towards start of construction works on site. Normally the participants of the Kick Off meeting includes

• Site Acquisition(SA) Representative
• CW representative
• Actual Owner or his representative of leased property of site
• CW Sub Contractor’s team lead/site supervisor (along with his team , with all measuring and marking tools)

CW representative have to understand that once s/he will have accepted the site at the time of kick-off, without any report, CW is going to be responsible