MEDC 02 ( 1901 ) DTZS  
 
                                        ICS: 91.080.10                                                                                                                                                                                              
                                                                                     
 
 
 
©TBS 20 23  First Edition  2023  DRAFT TANZANIA STANDARD  
 
 
 
Steel towers for communication  services  — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS  
 MEDC 02 (1901) DTZS  
ii 
©TBS 2023  – All rights reserved  This Tanzania Standard was published under the authority of the Board of Directors of Tanzania Bureau 
of Standard s 2023 -xx-yy. 
 
Tanzania Bureau of Standards (TBS) is the statutory national standards body for Tanzania, established 
under the Standards Act No. 3 of 1975 , amended by Act No. 2 of 2009.  
 
The Mechanical Engineering Divisional Standards Committee (MEDC) unde r whose supervision this 
Tanzania Standard was prepared consists of representatives from the following organizations:  
 
            *College of Engineering and Technology (CoET), University of Dar es Salaam  
 National Institute of Transport (NIT)  
            *National Development Corporation (NDC)  
*Dar es salaam Institute of Technology (DIT)   
Ministry of Wo rk 
            Weights and Measures Agency (WMA)  
Tanzania Industrial Research and Development Organization (TIRDO)  
Confederation of Tanzania Industries (C TI) 
            *Aluminium Africa Limited (ALAF)  
 
The organization marked with an asterisk (*) in the above list together with the following were directly 
represented on the Technical Committee entrusted with the preparation of this Tanzania Standard:  
 
Tanzania Automotive Technology Centre (TATC)  
Trans Auto Parts Company Limited (TAPCO)  
MM Integrated Steel Mills.  
 
 
 
 
 
 
 
 
 
 
 
Tanzania Bureau of Standards  
P O Box 9524  
Dar es Salaam  
Tel:  022 2450206/2450298/2450949  
Fax: 022 2450959  
E-mail: info@tbs.go.tz  
 
 
 
 
 
 
ISBN: 978-9987 -11-359-0MEDC 02 (1901) DTZS  
1  ©TBS 2023 – All rights res erved  
  Steel towers for communication services — Specification  
 
 
0 Foreword  
 
Mobile communication networks and broadcasting services require supportive infrastructure to enable 
communication services be delivered. Network facilities including towers and masts  are the lattice 
structures of either triangular or rectangular  base  section s that comprise  leg and bracing  members  used 
in the telecommunication  and broadcasting  sector . Communication towers  are available in two major 
types; self-supporting tower s and guyed mast s depending o n the way towers are supported .  
 
For the purpose of deciding whether a particular requirement of this standard comply  with the final value, 
observed or calculated expressing the result of a measurement or test  shall be rounded off in accordance 
with TZS 4, Rounding off numerical values . 
 
 
1 Scope  
 
This standard specifies  the technical requirements for  the designing, fabrication, installation, inspection 
and maintenance operation s for steel  towers , masts  and the ir accessories  used in  communication  
industry .  It covers  monopole s, roof mount / rooftop , self-supporting t owers and guyed mast s. 
 
This standard  ensure s that the  performance, reliability, public safety  and sa fety of working personnel and 
equipment during  installation, operation, inspection  and maintenance . The requirements  of the local 
operating environment are also taken into consideration by this standard  alongside the need to achieve 
substantial conformit y with applicable international best practices.  
 
 
2 Normative References  
 
The following standards contain provisions that, through reference in this text, constitute provisions of this 
standard. All standards are subject to revision and, since any reference to a standard is deemed to be a 
reference to the  latest edition of that standard, parties to agreements based on this standard are 
encouraged to take steps to ensure the use of the most recent editions o f the standards indicated below:     
 
FTZS 3457:2022 , Code of practise for design and construction of foundations  
FTZS 3491 -1/ ISO 10721 -1, Steel structures - Part 1: Materials and design  
FTZS 3491 -2/ ISO 10721 -2, Steel structures - Part 2: Fabrication and erection  
TZS 172/ISO 4014, Fasteners — Hexagon head bolts — Product grades A and B  
TZS 173/ISO 4016, Fasteners — Hexagon head bolts — Product grade C  
TZS 174/ISO 4032, Hexagon regular nuts (style 1) — Product grades A and B  
TZS 175/ISO 4033, Hexagon high nuts (style 2) — Product grades A and B  
TZS 176/ISO 4034, Hexagon regular nuts (style 1) — Product gra de C  
TZS 2893/ ISO 1461, Hot dip galvanized coatings on fabricated iron and steel articles — Specifications 
and test methods  
TZS 2630 -1/ ISO 9606 -1, Qualification testing of welders - Fusion welding - Part 1: Steels  
TZS 3082/ ISO 10684, Fasteners — Hot dip  galvanized coatings  
ISO 377, Steel and steel products — Location and preparation of samples and test pieces for mechanical 
testing  
ISO 898 -1, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, 
screws and studs with sp ecified property classes — Coarse thread and fine pitch thread  MEDC 02 (1901) DTZS  
2  ©TBS 2023 – All rights res erved  
 ISO 898 -2, Mechanical properties of fasteners made of carbon steel and alloy steel — Part 2: Nuts with 
specified property classes — Coarse thread and fine pitch thread  
ISO 898 -3, Mechanical pro perties of fasteners made of carbon steel and alloy steel — Part 3: Flat 
washers with specified property classes  
ISO 2394 , General principles on reliability for structures  
ISO 14713 -2, Zinc coatings — Guidelines and recommendations for the protection again st corrosion of 
iron and steel in structures — Part 2: Hot dip galvanizing  
ISO 15350, Steel and iron — Determination of total carbon and sulfur content — Infrared absorption 
method after combustion in an induction furnace (routine method)  
ISO 17054, Routin e method for analysis of high alloy steel by X -ray fluorescence spectrometry (XRF) by 
using a near -by technique  
ISO 19272, Low alloyed steel — Determination of C, Si, Mn, P, S, Cr, Ni, Al, Ti and Cu - Glow discharge 
optical emission spectrometry (routine m ethod)  
ISO 10333 -4, Personal fall -arrest systems  — Part 4: Vertical rails and vertical lifelines incorporating a 
sliding -type fall arrester  
ASTM A 143, Standard Practice for Safeguarding Against Embrittlement of Hot -Dip Galvanized Structural 
Steel Products  and Procedure for Detecting Embrittlement  
ISO 17637, Non -destructive testing of welds — Visual testing of fusion -welded joints  
ISO 17635, Non -destructive testing of welds — General rules for metallic materials  
EN 1993 -3-1, Design of steel structures – Part 3-1: Towers, masts and chimneys – Towers and Masts  
EN 1993 -1-11, Design of steel structures - Part 1 -11: Design of structures with tension components   
ANSI/TIA -222-H, Structural Standard for Antenna Supporting Structures and Antennas  and small wind 
turbine support structures  
BS EN 10025 -2, Hot rolled products of structural steels. Part 2: Technical delivery conditions for non -alloy 
structural steels.  
 
 
3 Terms a nd Definitions  
For the purposes of this Tanzania Standard, the fol lowing definitions shall appl y: 
 
3.1 Lattice  structure  
a structure  which is topologically ordered, three -dimensional open -celled structures composed of one or 
more repeating unit cells  made up of l eg and bracing  member s. 
 
3.2 Tower  
a lattice structure  of either self -supporting or guye d (cable supported)  that consists of an open network of 
metal braces and is usually triangular or square in plan, d esigned to support antennas for 
telecommunications and broadcasting services.  
 
3.3 Self-supporting tower  
a free-standing  lattice  structure wh ich is tapered  in shape and  consists of an open ne twork of metal 
braces and is usually triangular or square in plan , designed to support antennas for telecommunications 
and broadcasting  services . 
 
3.4 Monopole  
a self -supporting pole/post which consists of a single vertical pole fixed into the ground and/or attached to 
a foundation , designed to support antennas for telecommunications and broadcasting  services . 
 
3.5 Mast  
a lattice structure  of either self -supporting or guyed (cable supported ) which consists o f an open network 
of metal braces designed to support antennas for telecommunications and broadcasting  services . 
 
 
 
 MEDC 02 (1901) DTZS  
3  ©TBS 2023 – All rights res erved  
 3.6 Guyed mast 
a lattice structure  which is supported in whole or in part by cables anchored to the ground , consisting of 
an open network o f metal braces , designed to support antennas for telecommunications and broadcasting 
services . 
 
3.7 Roof m ount/ Rooftop  
a tower , mast or pole/post  used in elevating signals above roof interference or any other obstruction  
designed to support antennas for t elecommunications and broadcasting services . 
 
3.8 Antenna  
a device used to collect or  radiate electromagnetic waves  for transmission and reception of signals used 
in telecommunications and broadcasting services , including directional antennas, such as pane ls, 
wireless cable and satell ite dishes, and omnidirectional antennas, such as whips, but not including 
satellite earth stations.  
  
3.9 Leg member   
a member  forming the main  load-bearing components of the structure.   
 
3.10 Bracing member  
a member  other tha n legs carryi ng the horizontal forces due to the imposed loads on the structure . 
 
3.11 Communications tower  
a tower , mast or m onopole  (either  a self -supportin g or guyed ), built to support one or more antenna (s) 
used in  transm ission and reception of signals  for telecommunications and broadcasting services . 
 
3.12 Candela  
the base unit of light/ luminous intensity in the International System of Units , it is luminous power per unit 
solid angle emitted by a point light source in a particular direction . 
 
3.13 Setback  
the minimum distance required around any building or structure  that must be set aside from a street or 
road or river or shore  or flood  plain any other place which is deemed to need protection .  
 
3.14 Regulator  
the relevant authority responsible for r egulating the electronic and postal communication sector in 
Tanzania .  
 
3.15 Reliability  
a probability that the system will perform its function/tasks under the designed load conditions for a 
specified period, or  a probability that a given item will indeed  survive the given service environment and 
loading for a prescribed period of time.  
 
3.16 Safety  
the ability of a system not to cause harm to human  (injuries or loss of life)  or damage to another sytem . 
 
3.17 RF Hazard Area  
An area with exposure to very hi gh radiofrequency  intensities that can result in heating of biological tissue 
and an increase in body temperature . 
 
3.18 Co-location  
means the accommod ation of two or more service provider ’s switches, antennas or other electronic 
communications equipment in, or on a single  steel  tower  within a single location . 
 
 
 
 MEDC 02 (1901) DTZS  
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 4 Symbols and Abbreviations  
4.1 For the purposes of this document, the symbols listed in Table 1  apply.  
 
Table 1: Symbols  
Symbol  Unit Description  Reference  
Einc V m-1 Incident E -field strength:  10.7 
Hinc A m-1 Incident H -field strength  10.7 
Sinc W m-2 Incident Power density  10.7 
fM MHz Frequency  10.7 
fG GHz Frequency  10.7 
Rm MPaa Tensile strength  7.2.2  
Rp0.2 MPaa 0.2 % proof strength, 
plastic extension  7.2.2  
a 1 MPa = 1 N/mm2. 
 
4.2 For th e purposes of this document, the abbreviations listed in Table 2 apply.  
 
Table 2: Abbreviations  
Abbreviations  Description  Reference  
TCRA  Tanzania Communications 
Regulatory Authority  10.7 
TCAA  Tanzania Civil Aviation Authority  6.1, 6.9, 6.10, 10.6  
ICAO  International Civil Aviation 
Organization  6.9, 6.10,  
TANESCO  Tanzania Electric Supply 
Company Limited  10.5 
ICNIRP  International Commission on 
Non-Ionizing Radiation 
Protection  10.7 
TAEC  Tanzania Atomic Energy 
Commission  10.7 
RF Radio Frequency  10.7 
OSH A Operation Safety and Health 
Authority  11.1 
NEMC  National Environment 
Management Council  10.6 
 
 
5 Classifications  of Communication Facilities  
This standard  recognizes  the following types of telecommunication facilities , namely;  
 
5.1 Monopole  
a) Monopole co nsists  of tapered steel tubes that fit over each other t o form a stable pole.  
b) A monopole may be guyed or self -suppor ted and be fitted with climbing rungs where necessary. It 
should have the following features:  
i. Sections should be made from hollow, heavy d uty, thick steel tubes, flanged steel tubes 
or low -alloy, high -strength steel.  
ii. Each shaft section should be a constant -tapered hollow steel section  MEDC 02 (1901) DTZS  
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 iii. Slip joints should be designed with a minimum of 1 1/2 times  the pole diameter at the 
splice.  
iv. Pipe diameter sh ould decrease from bottom to top  
v. Monopole are to be made from galvanized holl ow steel pipes or high strength steel and 
designed for a variety of multi -user configurations and finishes to meet local aesthetic 
requirements.  
vi. The pipes shall be tapered to ensu re that one  pipe base fits into the top of another until 
the desired height is achieved. A joint in the arrangement should have an overlay 
between the two adjacent pipes.  
vii. The depth of the overlay, the base wid th and the number of pipes in a particular 
mono pole shall be determined by expected height of a tower, the thickness of the pipe 
walls, the base diameter  and whether the tower shall be guyed or not.  
 
 
Figure 1: Monopole  
 
 MEDC 02 (1901) DTZS  
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 5.2 Guyed Masts  
a) These are towers that are stabilized by tethered wires  
b) Guyed tow ers shall be designed and installed in  the manner  of the following specifications and 
recommended practices:  
i. Guyed masts may be in lattice, triangular or square, tapered or straight, as well  as 
monopole structural forms.  
ii. Guyed masts shall be supported and held in position by guy wires or ropes.  
iii. Mast Guy Ropes shall be made from pre -stretched steel only. For every mast,  the 
specified minimum strength of the guy wire shall be the maximum tension  likely to occur 
in the worst loading condition.  
iv. Guy wires must n ot be over tightened in the installation of guy towers in order  to avoid 
excessive tension which may cause alignment problems, cable  rupture and permanent 
wrapping of tower structural parts.  
v. All sections must be straight square sections to eliminate potent ial problems  associated 
with twisting or the need to shim the legs.  
vi. Typical tower sections are to have brace configuration with horizontals (z, x or  k) and 
pivot base sections. These tower -structures should be wholly of steel,  modular and hot -
dip galvanize d. 
vii. Sections can be of the same face width but in the event that the tapered type  is 
considered, the design should be with junction flanges.  
viii. Guyed towers should have tube or solid legs with solid bracing which increases  the tower 
rigidity to allow for the t wist and sway.  
ix. Guy wires are to be engineered with precision and a minimum safety factor of  2.0 applied 
to the design.  
x. The design, based on the load calculations would determine working load and  the break 
strength required of the guy wire a nd ultimately th e choice of the size and grade of the 
wire.  
xi. The choice of each guy earth screw anchor wo uld be dependent on its holding power in 
the soil, which is a function of its di ameter and length to be used to compute the minimum 
number of guys required.  
xii. As a genera l rule, guys should be planted in three directio ns at 120 ◦ apart from each 
other. The distance from the base of t he tower to the guy anchor base should be one 
quarter of the height of the tower.  
 
 
Figure 2: Guyed Mast  MEDC 02 (1901) DTZS  
7  ©TBS 2023 – All rights res erved  
  
5.3 Self -Supporting Towers  
a) Self-supporting towers are f ree-standing lattice structures  
b) The us e of self -supporting towers with tapered sec tions, and face width that vary according to 
height and load capacity is recomm ended when land availability is limited provided that it is 
technically feasible to install them.  
c) Self-supporting towers shall be des igned and const ructed as Lattice structures in the manner  
described in this standard and shall have the following features:  
i. Triangular or square structure  
ii. Tube legs, angle legs, lattice legs or solid round legs  
iii. Sections in steel angle steel or steel tubes  
iv. Steel angle cross bracing.  
v. Tapered sections  
vi. Face widths vary according to height and load capacity.  
vii. Rest platforms provided every 45m of height  
viii. Work platforms provided at all height where antennas are to be installed  
ix. Fitted with climbing ladder  
 
Standard s upport forms for lattice structures are specified as follows:  
i. Lattice Leg  
ii. Angle Leg  
iii. Tube Leg / Solid Round Leg  
 
   
  
Figure 3 : Self-supporting lattice tower  
 MEDC 02 (1901) DTZS  
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 5.4 Roof Mount / Rooftop  
a) Roof mounts are an inexpensive way of elevating sig nals above roof interf erence or any other 
obstruction.  
b) The design and installation of roof mounts shall take cognizance of the following specifications 
and recommended practices:  
i. Structural checks must be made to ascertain the  capability of a chosen roof to withstand 
the additi onal load being imposed on it by t he structure and the entire antenna array it will 
support.  
ii. All roof mounted masts or towers must  be certified by the building’s structural engineer 
before installation.  
iii. As a general rule, roof mounts should be limite d to l ight weight structures of low heights 
and support minimal dead and dynamic loads.  
iv. Roof mounts can be installed in the penet rating or non -penetrating modes and can be 
self-support or guyed. However n on- penetrating roof mounts are most suitable for flat 
surfaces.  
 
5.5 General Features of Towers  
a) In constructing tower legs, pipes or angle steel should be used . 
b) Bracings should be of angle steel construction.  
c) Mast sections, when made from steel pipes, should be joined to each other through joint plates 
welded t o the base of each section. The width of the mast section joint plates should be double 
the width of the wall of the pipe they are supporting.  
d) Gussets should be used in the strengthening of the weld joint between the base plate and the 
tower section.  
e) Each  plate should have four ho les drilled to accommodate four  bolts, nuts and washers.  
f) When bolting sections together, bolts should be placed upside down with washers and nuts on 
topside of plates, the connecting face of plates should not be painted.  
g) Lock nu ts must be used but nuts on bolts may be clinched if lock nut is not utilized.  
h) Lock washers and lock nuts should be used on antenna support steel work and dish panning 
arms in order to avoid loss of signals.  
i) When a tower is made from angle steel, section s should be joined to each other through 
appropriately sized flanges, bolts, washers and lock nuts.  
j) There should be adequate application of bracing to prevent towers been exposed to torque that 
may result in loss of signal during strong winds speeds.  
 
 
6 General Requirements  
 
6.1 Firefighting equipment  
Each facility of c ommunication towers  shall be equipped with the appropriate fire extinguisher to be used 
in case of fire emergency.  
 
6.2 Tower h eight  
The maximum height of steel towers for c ommunication services  shall be subjected to the approval of the 
relevant authority, Tanzania Civil Aviation Authority (TCAA).  The maximum height for steel towers (lattice 
and mono poles ) mounted on top of buildings (rooftops/roof mount s) shall not exceed 12m.  
 
6.3 Parkin g area 
Adequate parking spaces shall be provided for use by maintenance personnel on each site so that right -
of-way for parking on a public road will not be necessary. A minimum of one parking space shall be 
provided per user located on the facility site.  
 
6.4 Signage  
No signage, lettering, symbols, images, or trademarks in excess of 1200 cm2 shall be placed on or affixed 
to any part of a tower, mast, antenna or antenna array fencing other than as required by the regulator  for MEDC 02 (1901) DTZS  
9  ©TBS 2023 – All rights res erved  
 the purposes of identifying the  operator.  No adverts shall be allowed on any of the communication 
structures.  
 
6.5 Antenna Mounting Frames  
Frames for mounting antennas on towers or masts shall be designed upon  consideration of the type of 
tower structure and the type, weight and size of  the antenna. The frames shall be made from galvanized 
steel, stainless steel or aluminium and  care must be taken to ensure that there are no welded parts, and 
that bolts and  nuts are used for implementing joints.  
 
6.6 Metallic Coatings  
All steel materials to be used in the finishing of the superstructure shall be hot -dip galvanized before 
painting . 
 
6.7 Painting  
All tower  structures must be painted  in accord ance  to Tanzania Civil Aviation Authority (TCAA)  guidelines 
on safety regulation for aerodromes and grou nd aids and /or International Civil Aviation Organization 
(ICAO) guidelines on paint instructions for obstructions  as specified below:  
  
a) For structures up to 212 m, the structure shall be given seven equal bands of red and white paint 
or orange and white pa int.  
b) For structures above 212 m, nine bands of paint in alternating red and white or red and orange.  
c) In all cases the top and bottom of mast or tower must be painted red or orange.  
d) Paint shall be non -gloss finish (matt).  
 
6.8 Obstruction Lighting / Avia tion Warning  Lights  
All lattice structures  (mast and tower ) must conform strictly to TCAA and ICAO  guidelines with respect to 
obstruction lighting of tall structures  as specified below:  
a) For every 50 m  of height above ground level, a  tower shall have instal led on it, one lamp on top 
and two lamps at the sides.  
b) Obstruction lamps shall be maintained in a workin g condition at all times on all structures within 
15 km of  an airport or helipad.  
 
Light intensity and colour specifications should be as provided hereu nder in Table 3. 
 
Table 3: Light intensity and colour specifications  
Tower Height  (m) Light Intensity  (in candelas ) Light Colour  
Below 45  10 – 1,600  Red and fixed  
Between 45 and 150  1,601 – 4,000  Red and flashing  
Greater than 150  4,001 – 20,000  White Fl ashing  
 
6.9 Security fencing  
Security fencing, where installed, shall be a wrought iron, barbed wire, or steel chain link fence with 
evergreen hedge or a masonry wall not less than 2.5 m in height.  The security fence has to be provided 
even when the steel  tower is located in the  compound  of institution  or company with the fence . 
 
6.10 Decommissioning  of steel towers  
The steel tower when removed from service (decommissioned) should be removed from site within six 
months by the owner and/or the service provi der and the erection of a new one capable of 
accommodating other antennas should be considered . The steel tower shall be  decommissioned  when it 
poses a safety concern or its condition is incapable of supporting  switches,  antennas  or other equipment . 
 
6.11 Tower site cleanliness  
The owner steel tower  and/or the service provider should ensure that all  obsolete or abandoned  
equipment installed on the steel towers are completely removed from the site  and the general cleanliness  
of the site including proper dres sing of electrical and signal cable s.  MEDC 02 (1901) DTZS  
10  ©TBS 2023 – All rights res erved  
  
6.12 Tower Co-location   
An individual or entity  intends to construct a tower must demonstrate that all reasonable steps have been 
taken to investigate tower sharing  (Co-location)  before applying to the permitting age ncies to construct a 
new tower within a specified radius of 400m of the proposed site.  
 
 
Where tower heights are shorter, a smaller search radius can be used as follows:  
(a) Two towers above 46m, a radius of 400m shall apply; and  
(b) Two towers below 46m towers, a radius of 300m shall apply.  
 
However , the following factors may inhibit co -location:  
(a) Lack of structural capacity to support weights, orientation, heights and wind loads from 
additional equipment.  
(b) Lack of ground space to accommodate shelte r for base stations and other equipment.  
 
A written documentation in a form of a co -location statement, which indicates the reason why co -location 
was not possible,  shall be submitted when co-location is not technically feasible . The applicant shall 
submit  the co -location statement to the permitting agencies on application for a new site.  
 
 
7 Design requirements   
 
7.1 Design  requirements  
The steel  towers shall be designed according to any recognized standard /code  including FTZS 3491 -1/ 
ISO 10721 -1, FTZS 349 1-2/ ISO 10721 -2, EN 1993 -3-1, EN 1993 -1-11 or ANSI/TIA -222-H. The 
foundations shall be designed according to  FTZS 3457. The g eneral principles on reliability for structures  
are provided in ISO 2394 . 
 
7.1.1 Loading   
The predominant load on tower structures  shall be wind load.  Towers shall be analyzed under three (3) 
specific types of loading  for structural integrity : 
a. Wind  
b. Environmental  
c. Seismic  
 
The steel tower co-location should  be considered during designing.  
 
The possible antenna load, possible wind speed  and allowable t ilt and sway angle should be as shown in 
Table 4 and Table 5. 
 
Table 4: Loading  requirements for self -supporting steel towers  
Parameters  Categories  
Very L ight Light  Medium  Heavy D uty 
Possible antenna 
load (in m² ) from 4 to 6  from 6 to 10  from 10 to 20  from 20 to 25  
Possible wind 
speed (in km/h ) from 120 to 200  from 120 to 200  from 120 to 200  from 120 to 200  
Tilt and sway (in 
degree ) ± 1° ± 1° ± 1° ± 1° 
Application  Very light antenna  
load Light antenna  
load Medium antenna  
load Heavy dut y 
antenna  
load 
 
 MEDC 02 (1901) DTZS  
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Table 5: Loading requirements for guyed masts  
Parameters  Categories  
Very Light  Light  Medium  Heavy Duty  
Possible antenna 
load (in m² ) from 1 to 3  from 3 to 8  from 8 to 20  from 20 to 50  
Possible wind 
speed (in km/h ) from 120 to 200  from 120 to 200  from 120 to 200  from 120 to 200  
Tilt and sway (in 
degree)  ± 1° ± 1° ± 1° ± 1° 
Application  Very light antenna  
load Light antenna  
load Medium antenna  
load Heavy duty antenna  
load 
 
7.2 Materials  requirements  
 
7.2.1 General requirements  
Communi cation facilities  (towers, masts, and mono poles ) shall be made of structural  steel materials  which 
will be suitable for hot dip galvanizing . 
 
7.2.2 Structural membe r requirements  
All members shall be made of structural steel material complying with BS EN 1 0025 -2:2019. Therefore,  
leg and bracing members shall be of structural steel grades of S235JR, S235JO or S355JO complying 
with Table 6 and 7. 
 
Each structural member shall be made of hot dip galvanized structure steel sections  before being painted . 
All str uctural members shall be hot dipped galvanized according to TZS 2893/ISO 1461.  
 
Table  6: Chemical composition for product analysis  
Designation  Method 
of 
deoxida
tion C in % max.  
 
For nominal 
product thickness 
in mm  Si 
% 
Max Mn 
% 
Max P 
% 
Max S 
% 
Max N 
% 
Max Cu 
% 
Max Other  
% 
Max 
Steel 
name  Steel 
number  ≤ 16 > 16 
≤ 40 > 40c 
S235JR  1.0038  FN 0.19 0.19 0.23 - 1.5 0.045  0.045  0.014  0.60 - 
S235JO  1.0114  FN 0.19 0.19 0.19 - 1.5 0.040  0.040  0.014  0.60 - 
S355JO  1.0553  FN 0.23 0.23i 0.24 0.6 1.7 0.040  0.040  0.014  0.60 - 
FN – Rimming steel not permitted;  
 
Table 7: Mechanical properties – Tensile test properties at room temperature  
Designation  Minimum yield strength, ReH 
MPa 
Nominal thickness , mm 
 Tensile strength , Rm  
MPa 
Nominal thickness,  mm Other  
% 
Max. 
Steel 
name  Steel 
number  ≤ 16 > 16 
≤ 40 > 40 
≤ 63 > 63 
≤ 80 > 80 
≤ 100 > 100 
≤ 150 < 3 ≥ 3 
≤ 100 > 100 
≤ 150 
S235JR  1.0038  235 225 215 215 215 195 360 - 510 360 - 510 350 - 500 - 
S235JO  1.0114  235 225 215 215 215 195 360 - 510 360 - 510 350 - 500 - 
S355JO  1.0553  355 345 335 325 315 295 510 - 680 470 - 630 450 - 600 - 
 
7.2.3 Test method s 
Location and preparation of samples and test pieces for mechanical testing  shall be done in accordance 
to ISO 377 . Tensile tests shall be carried out in accordance with  ISO 6892 -1. The manufact urer may 
choose between method A or B specified in ISO 6892 -1. MEDC 02 (1901) DTZS  
12  ©TBS 2023 – All rights res erved  
   
Test methods for chemical analysis shall be in accordance with ISO 17054 , ISO 15350  or ISO 19272  
depending on the elements to be analyzed and their content . The choice of a suitable chemical analytical 
method for analysis shall be as per agreement between purchaser and  manufacturer.  
 
Guidelines and recommendations for the protection against corrosion of iron and steel in structures  
should be as per  ISO 14713 -2. 
 
7.2.4 Fasteners  Requirements  
The fasteners shall be made of carbon steel  material.  
 
7.2.4.1 Fastener  Dimensions  and Tolerances  
The standard dimensions  and tolerances  of fasteners shall be used in accordance to the design 
requirements  and shall comply with either TZS 172 /ISO 4014, TZS 1 73/ISO 4016, TZS 174/ISO 4032, 
TZS 175/ISO 4033 or TZS 176/ISO 4034 . 
 
7.2.4.2 Mechanical properties of fasteners  
The mechanical properties of bolts made of carbon steel and alloy steel shall be in accordance to ISO 
898-1. The mechanical properties of nuts made of carbon steel and alloy steel shall be in accordance to 
ISO 898 -2. The mechanical properties of washers made of carbon steel and alloy steel shall be in 
accordance to ISO 898 -3. 
 
7.2.4.3 Coating properties of fasteners  
All fasteners shall have a  hot dip galvanized coatings  with local coating thickness of a minimum of 40 μm 
and the batch average coating thickness of a minimum of 50 μm  according to  TZS 3082/ ISO 10684 . 
 
Foundation a nchors  bolts  shall be  of hot dip galvanized coating complying  with a loc al coating thickness 
of a minimum of 40 μm and the batch average coating thickness of a minimum of 50 μm according to  TZS 
3082/ISO 10684.  
 
 
8. Fabrication and erection  
The fabrication of parts /members  and installation of the steel tower shall be done in ac cordance to FTZS 
3491 -2/ISO 10721 -2. The base of tower leg member shall be provided with draining hole  or slope angle 
to prevent water collection  and rusting.  The standard parts of the steel structure during installation and 
maintenance  shall not be modifi ed prior to approval by the designer/engineer.  
 
8.1 Fabrication  
Production will be controlled with suitable machines, appropriate work areas;  manpower to carry out the 
work will be suitable and competent to perform various works. During the manufacturing process safety 
precautions should be take n according standard practice for safeguarding against embrittlement of hot – 
dip galvanized structural steel products and procedure for detecting embrittlement ASTM A 143.  
 
8.1.1 Cutting, Drilling, Deformation and Punching of Members  
All members shall be carefully cut and holes accurately located, so that when members are assembled, 
the holes will be truly opposite e ach other before being bolted.  Holes in material having a thickness 
exceeding 15 mm  or exceeding the  diameter of the holes shall be drilled, other holes may be punched.  
 
The diameter of the hole shall not exceed that of the bolt by more than 1.5 mm,  measured before 
galvanizing for bolts 16 mm  and less and 2.0 mm  for bolts greater than 16 mm  measured bef ore 
galvanizing. In addition, the diameter of the die used in the punching machine shall exceed the diameter 
of the punch by the minimum practical amount so as to avoid excessive hole taper and consequent heavy 
bearing stress on the bolt shank. In no case shall the die exceed the punch diameter by more than 12.5 
percent.  
 MEDC 02 (1901) DTZS  
13  ©TBS 2023 – All rights res erved  
 Deforming of members by swaging, opening or closing angle legs shall only be permitted where this detail 
has no detrimental effect on the perform ance of the structural element. All punched  or drilled flanges of 
rolled steel sections shall have a width equal to or greater than 45 mm for nominal bracing and 50 mm  for 
load carrying members. All plates up to 12 mm  in thickness may be bent cold. Plates greater than 12 mm  
may be bent cold provide d the angle of set does not exceed 15o. 
 
All fabricated units shall be supplied in pieces to be bolt assembled and shall be based on the principles 
contained in  steel structures . All components shall be fabricated using jigs and machines such that close 
tolerances are maintained and burred and sharp edges, weld spatter, weld slag and galvanizing slag are 
avoided.  The steel shall be in all cases free from blisters, scale, laminations or any other defects.  All 
members shall be carefully cut and holes accurate ly located, so that when members are assembled, the 
holes will be truly opposite each other before being bolted.  
 
8.1.2 Welding  
All welding shall be carried out by qualified welders experienced in th e type of work covered by this 
specification according t o TZS 2630 -1/ISO 9606 -1. The welder  shall check the welding visually to make  
sure it meets the requirements specified in the ISO 17637 .The n on-destructive testing of welds  shall be 
carried out using any standard test methods recommended by ISO 17635 .  
 
8.1.3 Finishing  
The surface of all welds shall be smooth and free from sharp contour changes.  
The all burrs and sharp edges shall be removed from all steelwork before galvanizing.  
Welded end plates and contacting surfaces of parts to be bolted shall be free f rom distortion which would 
prevent the connecting faces from being in full contact when bolted.  
 
8.2 Erection  
Before galvanizing, all members shall be stamped with an alphanumeric mark number to identify the 
member. This marking shall be carried out in suc h a manner as to enable it to be clearly read after 
galvanizing.  
 
For roof mount/ rooftop mast s and tower s the base of the tower is mounted on concrete or steel frame 
(consists of I -beams or inverted I -beams) with the frame fixed on the rooftop existing con crete 
columns/pedestals. For rooftop pole the base of the pole is fixed with steel dowels drilled into the roof.  
 
8.3 Tolerances  on fabrication and installation  
8.3.1 Overall Height  
The overall height of an assembled structure shall be within +1% and -1/2%  of the specified  height, not to 
exceed +1.5 m  or -0.6 m . 
 
8.3.2 Guy Tensions  
The maximum deviation from the design initial tension shall be  
(i) ± 10% for guys up to and  including 25 mm  diameter and  
(ii) ± 5% for guys greater than 25 mm  diameter, of  the specified  design initial tension at an 
anchorage, corrected for the ambient temperature.  
 
8.3.3 Plumb  
The horizontal distance between the vertical centerlines at any two elevations shall not exceed  0.25 
percent  of the vertical distance between the two elevations.  
 
8.3.4 Twist  
The twist between any two elevations shall not exceed 0.5 degrees in 3m.  The maximum  twist over the 
structure height shall not exceed 5 degrees . 
 
8.3.5 Slip Splice  
The slip splice length tolerance shall not exceed 10%  of the design slip splice length. Splices  shall be 
pulled together to ensure firm contact.  MEDC 02 (1901) DTZS  
14  ©TBS 2023 – All rights res erved  
  
8.3.6 Straightness  
The straightness of the individual members shall be within a tolerance of 1 in 500  but not more  stringent 
than 1.6 mm  of the length between points which are laterally supp orted.  
 
8.3.7 Measurements  
Measurements shall be taken at a time when the wind velocity is less than 4.5 m/s  at ground level and 
with no ice on the structure or the guys.  
 
 
8.3.8 Take -Up Devices  
For initial installations, the minimum take -up adjustment ava ilable after the structure is plumb  and the guy 
tensions are set, shall be:  
a) 152 mm for guys wi th nominal diameter of 13 mm or less;  
b) 254 mm for guys with nominal  diameter greater than 13 mm. 
 
 
9 Earthing a nd lightning  protection  requirements  
 
9.1 Gene ral 
a) All masts shall be grounded and the earth resistance  measured at the earth terminal block shall 
be less than 5 ohms . 
b) A lightning air terminal (Faraday Rod) shall be mou nted on mast top and a vertical copper earth 
wire or tape run down the sid e of one m ast leg to ground and connected to the earth at the 
terminal box.  
c) Due recognition  should be taken of the fact th at the most important factor in getting a good 
earthing is the use of good quality m aterials for installation. Care should be taken to ensure th at 
the earthing and lightning protection design and  methods  are followed.  
 
9.2 Earthing  
a) Earthing and Lightning protection shall be provided i n all completed towers sites to protect 
equipment from damage and personnel from harm which may result from excessi ve voltages 
during a lightning strike.  
b) The arrangement shall be such that lightning disc harge current must be prevented from entering 
equipment rooms.  
c) Equipotential conditions shall be maintained throughout the site by bonding.  
d) Due recognition must be take n of the following:  
i. The resistance achievable in an earth installat ion is directly proportional to the resistivity 
of the soil at the depth to which the earth rod has been driven.  
ii. When the soil resistivity of a site is not k nown it can be measured without excavation by 
using a direct reading meter and earth spikes.  
iii. It can also be read out from tables if soil type is accurately known.  
iv. Resistivity at any depth is related to the diamet er of the earth rod, the target resistance 
and the depth to which the earth electrode is driven into the soil by:  
R = ( ρ / 275L) ×  log10 (400L / d) 
Where R is the target resistance  
ρ is the resistivity of the soil  
L is the length of electrode in meters  
d is the diameter of electrode in cm  
v. An accurate assessment of the soil resist ivity should be made around the tower base 
using a direct reading resistance  meters  to determine among other things the appropriate 
depth to drive in the c opper earth rods, the number of rods and the need for an earth mat, 
among other thing .  
 
 
 MEDC 02 (1901) DTZS  
15  ©TBS 2023 – All rights res erved  
 9.3 Lightni ng Protection  
a) Separate down conductors shall be installed from each air terminal (lightni ng spike)  and in 
addition, the structure shall also be a return path to the earth.  
b) These two systems shall be bonded together and  Lightning spikes shall be long enough  to give 
45ᵒ cone of protection over all aerials.  
c) Air terminations shall be made of copper rod, ha rd or medium – hard drawn, 12mm in diameter 
and d own conductors shall be made  from 25mm by 3mm soft annealed copper strip.  
d) The earth termination shall be inde pendent of the foundation reinforcement.  
e) Where rods are used as earth electrodes they shall  be driven into the ground to a depth of at 
least 2.4m in normal soil or the depth predetermined for the site from measurements.  
f) Longer lengths shall, when necessary , be built up of 1.2m lengths screwed onto each other with 
internal screw and socket joints.  
g) Where one earth electrode cannot obtain the s pecified resistance, additional electrodes should be 
connected in parallel and su ch additional electrodes may be those  provided for other down 
conductors.  
h) The distance between any two driven electrodes  shall be equal to their driven length.  
i) All connections between earth conductors and steelwor k shall be via sacrificial legs or brackets 
where copper would be in contact  with concrete and painted with bitumen or separated from the 
concrete with itemized paper.  
j) Earth conductor runs shall be straight as far as is practicable and where bends are unavoidable 
shall be smooth and of maximum radius.  
k) The resistance to ground of the e arth system shall be below 2 ohms.  
 
9.4 Protective Grounding  
a) Structures shall be directly grounded to a primary ground.  
b) A minimum ground shall consist of two, 1.2m long; 16 mm diameter  galvanized  steel ground rods 
driven not less than 2.4m into the ground,  180° ap art and  adjacent to the structure base.  
c) The ground rods shall be bonded with a lead of not smaller than 5 mm tinned bare  copper 
connected to the metal base of the structure of each leg of a tower.  
d) A similar ground rod shall be installed at each guy  anchor and connected to each  guy at the 
anchor in case of guyed towers.  
e) Self-supporting towers exceeding 1.5m in base width shall have one ground rod per  tower leg.  
f) All the earth rods shall be tied together to maintain an equipotential condition all  over the 
structure while top and bottom ground straps are to be bonded at both  ends.  
g) All equipment on a structure such as antennas, antenna supports and warning  safety lights shall 
be connected by a secondary ground.  
h) The earth of the tower shall be bonded to th e general earth of any adjoining  equipment room and 
all shall form a single earth.  
i) The maximum permissible resistance to earth shall be 2 ohms . 
 
 
10 Safety requirements  
 
10.1 Fall arrest systems   
Fall arrest systems shall be installed on every tower above the height of 45m.  A complete fall arrest 
system shall consist  of the rail and the trolley  according to ISO 10333 -4.  
a) The t rolley is a locking brake pawl attached to the harness of a climber.  
b) The t rolley moves freely along the Safety Rail with climber in n ormal climbing position  
c) In case of a slip trolley brakes remain locked un til the force is removed. Falls are instantly 
arrested when a sudden do wnward motion is applied to the Trolley. Trolley remains stationary 
once disconnected from the harness.  
 
10.2 An ti-Climb Shields  
Anti-Climb shields shall be installed on every tower above the height of 45m.  Anti-Climb shields consist of 
metal sheets bolted to tower legs. These are constructed to prevent unauthorized persons from cl imbing 
a tower. It is ideal for tower sites around schools and public areas where public safety is a concern . MEDC 02 (1901) DTZS  
16  ©TBS 2023 – All rights res erved  
  
10.3 Climbing Facilities  
a) Access Ladders  
i. Access ladders shall be made from hot dip galvanized steel or aluminium sections 
mountable on all tower types and monopoles amenable to insi de or outside mounting.  
ii. Climbing Ladders shall be of steel or aluminium depending on tower material and shall be 
provided with Safety cages, Landing places (rest and work platforms) and Protective 
finishes.  
iii. Ladders shall be attached to the tower structure.  
iv. The lowest point on the ladder shall be at a height of 3m to 4.5m a bove ground level and 
it shall run all through to the top of the structure.  
v. The ladder shall be so located that a clearance of at least 150mm at the rear of the 
ladders exists between the ladder and the structure.  
vi. Anti-climbing devices shall be provided on the structure to prevent access except from 
the climbing ladder.  
vii. The vertical separation between rest platforms shall be 20m.  
viii. Work and test platforms shall be located at those points wher e antennas are to be 
installed.  
ix. The cable tray not to be positioned in  front of the access ladder and instead to be either 
on the left side or right side of the ladder for the safety purposes.  
 
b) Platforms – Work / Rest / Test  
i. All platforms shall be readily accessible from the climbing ladder.  
ii. The access to all platforms and walkways fr om the vertical climbing ladder shall be from 
one direction only.  
iii. Platforms and walkways shall be designed to car ry a point load of 150kg  at any point 
without a deflection exce eding 6.0mm.  
 
c) Guard -rails 
i. Guard -rails shall be of height range between 0.9m and 1.1m a nd shall be  provided on all 
platforms, stairways and horizontal members used as  walkways.  
ii. They shall have an intermediate rail at half this height and a toe board not les s than 
150mm high.  
iii. The distance between any toe -board and the lowest guard – rail above it shall  not exceed 
750mm.  
iv. Widths of walk -ways and platforms shall not be less than 650mm.  
v. Walk -ways and surface used as working platforms or traversed to gain access  to 
platforms or traversed to gain access to working positions shall be provided  with anti -slip 
surface.  
vi. Guard rails and toe boards shall be attached at each stanchion and secured to  prevent 
rotation.  
 
10.4 Safety Enhancement  
Safety in the installation and u se of masts and towers are enhanced by the  following practices which shall 
be mandatory for all tower owners and installers.  
i. Tower assembly parts shall be standardized e.g. fasteners for the main  structure shall be 
of only one size, length and material.  
ii. Manual handing over of parts or tools between installers during tower  construction is 
forbidden.  
iii. All parts shall be labeled  in detail especially where the method of assembling  is not 
obvious.  
iv. Towers shall be structurally designed for simple assembly by the p romotion of  ease in 
fittings and elimination of small loose parts.  
v. On-site welding and riveting is prohibited.  Owners and installers of mast and  towers who 
engage in these practices shall be liable to pay a penalty to the  regulator . MEDC 02 (1901) DTZS  
17  ©TBS 2023 – All rights res erved  
 vi. All site connections sh all be by bolt and nut with a means provided for locking  the nut 
against loosening by vibration.  
vii. All nuts, bolts and washers shall be galvanized for easy assemblage . 
viii. Taper washers shall be used whenever the steel section shape requires their  use. 
ix. Bolt leng ths shall be such that with the locking device in place, a minimum of  one 
complete thread shall protrude beyond the nut.  
x. Bolt threads shall protrude inside the structure onl y. 
 
10.5 Proximity to Power Lines  
The communication tower s shall not be cons tructed  in close proximity to  high voltage (11kV and above) 
electrical power transmission  and distribution  lines. The nearest distance of a tower to a high voltage 
electrical power transmission line shall be according to  TANESCO specifications  shown in Table 8. 
 
Table 8: Minimum  safe distance from  high voltage  electrical power transmission  and distribution  
lines 
Electrical power transmission 
lines  (High Voltage in kV)  Minimum safe distance on each 
side from the center  line (in m)  Minimum total safe 
distance (in m)  
11 2.5 5 
33 5 10 
66 10 20 
132 20 40 
200 30 60 
330 40 80 
400 40 80 
 
10.6 Proximity to Aviation Sites and Other Environment  
No steel towers (irrespective of the hei ght) may be installed without prior approval and permits from  
relevant authorit ies, including NEMC, TCRA and TCAA . 
 
10.7 Public Exposure to the Electromagnetic Radiation (EMR)  
For the purpose of annual inspection , all the operators shall provide to regulator,  details of all their base 
stations coun trywide. This shall include the name of o perating company; their emiss ions; the height of the 
antenna above ground level; the date that tran smission started; the frequency range and signal 
transmission characte ristics. Both the regulator and o perator shall keep this information.  
 
The antenna shou ld not be less than 15m from the ground.  For roof mounted antennas, the trans mitting 
antennas should be kept away from the areas where people are most likely to be.  Antenna sites should 
be designed in su ch a way that the public cannot access such areas, th e nearest the publi c can be from 
an antenna should not be less than 3m. 
 
For each RF hazard area, an operator sh all ensure warning signs are in place in a location and in a 
manner that is appropriate so that they are clearly visible.  
 
The signal of the str ongest intensity should not land on the ground at a horizontal distance less than 
100m  from the foot of the antenna.  The beam of greatest radio frequency intensity from a base station 
sited within or near public areas (markets, parks, education facilities,  health facilities etc) shall not be 
permitted to fall on any part of the grounds or buildings of the institution.  
 
The operator shall avoid siting towers in or near wetlands, near known bird concentration areas or in 
habitat of listed as threatened or endangered species or in migratory bird’s routes.  
 
The operator shall comply wit h the guidelines established by  TAEC and  ICNIRP  for public exposure to 
radiation . Regular  independent random audits shall be carried out by regulator, TCRA to ensure 
conformity to  TAEC and ICNIRP guidelines  according to Table s 9, 10 and 11. 
 MEDC 02 (1901) DTZS  
18  ©TBS 2023 – All rights res erved  
 Table 9: Basic restrictions for electromagnetic field exposure from 100 kHz to 300 GHz, for 
averaging intervals  ≥ 6 min.  
Exposure 
scenario  Frequency  
range  Whole body average 
SAR (Wkg-1) Local H ead/ Torso 
SAR (Wkg-1) Local Limb 
SAR (Wkg-1) Local Sab 
(Wm-2) 
Occupational  100 kHz to 6 GHz  0.4 10 20 NA 
 >6 GHz to 300 GHz  0.4 NA NA 100 
General public  100 kHz to 6 GHz  0.08  2 4 NA 
 >6 GHz to 300 GHz  0.08  NA NA 20 
 
Note:  
1. ―NA‖ signifies ―not applicab le‖ and does not need to be taken into account when determining 
compliance.  
2. Whole -body average SAR is to be averaged over 30 min.  
3. Local SAR and S ab exposures are to be averaged over 6 min.  
4. Local SAR is to be averaged over a 10 -g cubic mass.  
5. Local S ab is to be averaged over a square 4 -cm2 surface area of the body. Above 30GHz, an 
additional constraint is imposed, such that exposure averaged over a square 1 -cm2 surface area of 
the body is restricted to two times that of 4 -cm2 restriction.  
 
Table 10: Reference  levels for  exposure , averaged over 30 min and the whole body, to 
electromagnetic fields  from 100 kHz to 300 GHz  (unperturbed RMS  values) . 
 
Exposure 
scenario  Frequency  
range  Incident E -field 
strength: E inc (V m-1) Incident H -field 
strength: H inc (A m-1) Incident Power 
density; S inc (W m-2) 
Occupational  0.1 – 30 MHz  660/f M0.7 4.9/f M NA 
 >30 – 400 MHz  61 0.16  10 
 >400 – 2000 MHz  3fM0.5 0.008f M0.5 fM/40 
 >2 – 300 GHz  NA NA 50 
General public  0.1 – 30 MHz  300/f M0.7 2.2/f M NA 
 >30 – 400 MHz  27.7  0.073  2 
 >400 – 2000 MHz  1.375f M0.5 0.0037f M0.5 fM/200  
 >2 – 300 GHz  NA NA 10 
 
Note:  
1. ―NA‖ signifies ―not applicable‖ and does not need to be taken into account when determining 
compliance.  
2. fM is frequency in MHz.  
3. Sinc, Einc and H inc are to be averaged over 30 min,  over the whole body space. Temporal and spatial 
averaging of each of Einc and Hinc must be conducted by averaging over the relevant square 
values.  
4. For frequencies of 100 kHz to 30 MHz, regardless of the far -field/near -field zone distinctions, 
compliance i s demonstrated if neither E inc nor H inc exceeds the above reference values.  
5. For frequencies of >30 MHz  to 2 GHz (a) within the far -field zone: compliance is demonstrated if 
either S inc, Einc or H inc does not exceed the above reference values (only one is r equired) : S eq may 
be substituted for S inc;  (b) within the radiative near -field zone, compliance is demonstrated if either MEDC 02 (1901) DTZS  
19  ©TBS 2023 – All rights res erved  
 Sinc or both E inc and H inc, does not exceed the above reference level values; and (c) within the 
reactive near -field zone: complianc e is demonstrated if  both E inc and H inc do not exceed the above 
reference values; Sinc cannot be used to demonstrate compliance, and so basic restrictions must 
be assessed.  
6. For frequencies of > 2 GHz to 300 GHz: (a) within the far –field zone: compliance i s demonstrated if 
Sinc does not exceed the above reference level values; Seq may be substituted for S inc; (b) within the 
radiative near -field zone, compliance is demonstrated if S inc does not exceed the above reference 
level values; and (c) within the reac tive near -field zone, reference levels cannot be used to 
determine compliance, and so basic restrictions must be assessed.  
 
Table 11: Reference levels for  local exposure , averaged over 6 min, to electromagnetic fields from 
100 kHz to 300 GHz  (unperturbed RMS values) . 
 
Exposure 
scenario  Frequency  
range  Incident E -field 
strength: E inc (V m-1) Incident H -field 
strength: H inc (A m-1) Incident Power 
density; S inc (W m-2) 
Occupational  0.1 – 30 MHz  1504/fM0.7 10.8 /fM NA 
 >30 – 400 MHz  139 0.36  50 
 >400 – 2000 M Hz 10.58 fM0.43  0.0274f M0.43  0.29 fM0.86  
 >2 – 6 GHz NA NA 200 
 >6 –  <300 GHz  NA NA 275/f G0.177  
 300 GHz  NA NA 100 
General public  0.1 – 30 MHz  671/f M0.7 4.9/fM NA 
 >30 – 400 MHz  62 0.163 10 
 >400 – 2000 MHz  4.72 fM0.43  0.0123fM0.43  0.058fM0.86  
 >2 – 6 GHz NA NA 40 
 >6 – 300 GHz  NA NA 55/f G0.177  
 300 GHz  NA NA 20 
 
Note:  
1. ―NA‖ signifies ―not applicable‖ and does not need to be taken into account when determining 
compliance.  
2. fM is frequency in MHz ; fG is frequency in GHz.  
3. Sinc, E inc and H inc are to be a veraged over 6 min, and where  spatial averaging is specified in 
Notes 6 –7, over the relevant projected body space. Temporal and spatial averaging of each of 
Einc and H inc must be conducted by averaging over the relevant square values (see eqn 8 in 
Appendix  A for details).  
4. For frequencies of 100 kHz to 30 MHz, regardless of the far -field/near -field zone distinctions, 
compliance is demonstrated if neither peak  spatial E inc or peak spatial H inc, over the projected 
whole -body space, exceeds the above reference level values.  
5. For frequencies of >30 MHz to 6 GHz: (a) within the far -field zone, compliance is demonstrated if 
one of peak spatial S inc, Einc or H inc, over the projected whole -body space, does not exceed the 
above reference level values (only one is requi red); S eq may be substituted for S inc; (b) within the 
radiative near -field zone, compliance is demonstrated if either peak spatial S inc, or both peak 
spatial E inc and H inc, over the psrojected whole -body space, does not exceed the above reference 
level val ues; and (c) within the reactive near -field zone: compliance is demonstrated if both E inc MEDC 02 (1901) DTZS  
20  ©TBS 2023 – All rights res erved  
 and H inc do not exceed the above reference level values; S inc cannot be used to demonstrate 
compliance; for frequencies >2 GHz, reference levels cannot be used to det ermine compliance, 
and so basic restrictions must be assessed.  
6. For frequencies of >6 GHz to 300 GHz: (a) within the far -field zone, compliance is demonstrated if 
Sinc, averaged over a square 4 -cm2 projected body surface space, does not exceed the above 
reference level values; S eq may be substituted for S inc; (b) within the radiative near -field zone, 
compliance is demonstrated if S inc, averaged over a square 4 -cm2 projected body surface space, 
does not exceed the above reference level values; and (c) within the reactive near -field zone 
reference levels cannot be used to determine compliance, and so basic restrictions must be 
assessed . 
7. For frequencies of >30 GHz to 300 GHz, exposure averaged over a square 1 -cm2 projected body 
surface space must not exceed twic e that of . 
 
 
11 Inspection  and maintenance requirements  
 
The scope of inspection and maintenance should cover all aspects that are relevant to the maintenance 
of structural integrity, and to the serviceability of the structure and its communications functi ons. 
 
Maintenance and inspection of stee l towers and antenna supporting structures should be performed by 
the owner /operator of the facility  on a routine basis.  The regulator shall be responsible for performing 
initial inspections of towers and masts befor e issuing the license and be responsible for verification of  
periodic inspections of towers and masts  done by the owner /operator . The owner /operator  of the network 
facilities (towers and masts) shall be responsible for performing the required maintenance a nd repair 
tasks as directed by the regulator.  
 
The inspection and maintenance records for every tower site shall be kept by the owner or operator and 
shall be readily accessible to the inspectors  or any duly authorized person from regulator upon request.  
 
11.1 Qualifications of inspection  and maintenance  personnel  
Both g round and aerial inspection and maintenance  should be performed by authorized personnel, 
qualified on working in heights  and its safety precautions  according to OSHA requirements . 
 
11.2 Inspection frequency  
Preventive maintenance inspection checks shall be done  by the operator/ owner  at least once in every 3 
years  for guyed towers and at least once in every 5 years  for self -supporting towers. Shorter inspection 
intervals of 2 years  for guyed  towers and 3 years  for self -supporting towers may be obligatory for 
structures in coastal regions, in  salty/corrosive  environments  and in areas that are frequently affected  by 
severe winds  (storms or cyclones) , earthquakes or vandalism.  
 
Routine inspectio n checks  shall be conducted to all towers  at least once in every year,  to assess the 
structural condition of the tower and support equipment by the operator/ owner and serviced as frequently 
as may be necessary, to m aintain the tower in a safe and best ope rating  conditions . The regulator  shall 
also conduct routine inspection checks  on facilities  least once in every year  to ensure compliance.  
 
Steel towers  in the  specific  location  shall be  subjected to either routine or preventive  inspect ion after 
occurrence  of the following environmental conditions:  
a) Severe  winds,  storms  and tropical  cyclones  
b) Other extreme conditions (like Floods ) 
c) Severe seismic events ( Occurrences  of an earthquake ) 
 
11.3 Inspection  tasks  
Inspections tasks should be undertaken by experienced crews with the appropriate equipment  as per 
Annex A . 
 
 MEDC 02 (1901) DTZS  
21  ©TBS 2023 – All rights res erved  
 The inspections should cover, as far as possible, the following:  
a) Loose or missing bolts.  
b) Fatigue cracking.  
c) Damage from structural overload.  
d) Vandalism (including rifle damage).  
e) Corrosion of galvanized s teelwork.  
f) Degradation of paint systems.  
g) Vibration.  
h) Lightning damage.  
i) Foundation deterioration and cracking.  
j) Loose or damaged guy wires and fittings.  
k) Ground surface erosion.  
l) Evidence of soil creep or landslides.  
m) Settlement.  
n) Earthing integrity.  
o) Auxiliary ant ennas, mountings and feed systems.  
p) Maintenance of safety facilities.  
q) Site security.  
r) Tower or mast verticality and twist.  
s) Navigation lighting.  
t) Condition of insulators.  
 
The inspection intervals need to be tuned to the operational environment and structural/ service functional 
needs. Structures that have known vibrational problems, or are in a very corrosive environment, or are in 
a very windy or ice environment may need more frequent inspections.  
 
The interval between maintenance inspections in particular wil l depend on factors such as : 
(a) Corrosion potential of the environment and the degree of protection required for   
maintenance of design reliability;  
(b) Importance of the structure to its service;  
(c) Severity of local conditions (i.e. wind, storms, cyclones  and earthquakes ); 
(d) Sensitivity to structural response; and  
(e) Influence of ground conditions.  
 
It is recommended that the interval between inspections should be according to the relative importance of 
the above factors.   
 
11.4 Maintenance tasks  
Mainte nance and repair tasks should be undertaken by experienced crews with the appropriate 
equipment  according to Annex B . The replacement of any structural members should be approached with 
caution and an engineering valuation may be necessary before work comm ences.  
 
On guyed masts, variation in guy tensions may be cri tical to the performance of the facility. Where 
inelastic construction stretch is  not removed from guys prior to installation, it may be necessary that re -
tensioning be  undertaken at the end of 12 to 18 months  after construction. Guy tensions should be 
maintained to within ±  5% of the design values.  
 
Maintenance crews should be aware of any electrical hazards, particularly radiation, while undertaking 
work on communication structures. Advice on the se aspects should be sought from the site owner.  
 
 
12 Marking, Labeling  and Packaging  
 
12.1 Member  marking  
All structural members or welded structural assemblies, except for hardware, shall hav e a part number. 
The part numbers shall correspond with the ass embly drawings. The part number is to be permanently MEDC 02 (1901) DTZS  
22  ©TBS 2023 – All rights res erved  
 attached (stamped, welded lettering, stamped o n a plate that is welded to the member, etc.) to the 
member before all protective coatings are  applied. The part number shall have a minimum character 
height  of 13 mm . 
 
12.2 Tower marking  
Each completed communication tower must have a n ame plate attached to one of its legs on which the 
following particulars are detailed:  
a) Name, address and telephone numbers of the owner, fabricator and installer  
b) Tower Height  
c) Base Section area (in m2) 
d) Tower loading requirements for Antenna (in m2), Cabling (in m2) and Weight (in kN)  
e) Maximum  wind speed considered  (in m/s or km/h)  
f) Payback Period (in years ) 
 
12.3 Antenna  marking  
The antenna of each tower shall contain the following particulars:  
a) Date of erection  
b) Height  
c) Number of antenna  
d) Operating Frequencies  
e) Location address  
f) Geographical coordinates  
g) Name of operator and licensee  
h) Effective Isotropic Radiated Power  
i) Records  showing inspection dates and types of inspections performed and detailed particulars of 
the inspector.  
 
12.4 Packaging and labeling  of parts  
All items of tower shall be dismantled except the cross -arms  for towers, according the drawings. All items 
of each part of tower shall be placed in separate bundles according to f abrication drawings (Material 
packing table). Bundles of steel angles shall be properly tied together: long items will be placed 
underneath;  small angles will be above. All bundles will be placed on a wood s keleton platform 
(consisting of deck boards and r unners) and secured with double 6 mm t hick galvanized steel strips at 
least in 3 places. Deck board shall have a minimum thickness of 25 mm.  
 
Cross -arms will be assembled with  bolts, nuts, screw washers according to  the drawings . The hangers 
and the vertic al diagonals will be tied to a cross -arm leg with double 6 mm thick galvanized steel strips at 
least in 3 places .  
 
Each packing shall contain a packing list with part draw ing and circle around each item that is in the 
package . Packing list will be in a wa terproof envelope.  All the plates shall be packed separately in boxes.  
The plates shall be threaded on galvanized wire 4 mm thick. An identification label  and box marking will 
be threaded on the same wire.  
 
There will be a separate label  for each part of the tower. The boxes shall be closed. Each label  will 
include the following information:  
i. Name of manufacturer  
ii. Country of manufacture  
iii. Type of tower  
iv. Name of part of the tower  
v. List of items marked on drawing  
vi. Bundle Weight (kg).  
 
 
 
 MEDC 02 (1901) DTZS  
23  ©TBS 2023 – All rights res erved  
 12.5 Site Identification , safety  and warning signs 
Each completed communication tower  site must be protected by a security fence that must have the 
following information on its entrance:  
i. Site identification  
A standard  way of identification for all towers  that communicates essential information to all 
parties including owner, operator and regulator .  
Example;  DAR -UBU -HAL-00111-06793918  
Whereby: - 
DAR - First three letters of region, Dar es Salaam  
UBU - First three letters of district, Ubungo  
HAL - First three letters of Owner/Operato r of the tower, Halotel  
00111 - Serial number of the tower  
06793918 - Coordinates expressed as the combination of latitude 06.79º and longitude     
                  39.18º  
 
ii. Safety  and w arning signs  
Radiation hazards  
Fall from height hazard  
Electric shock  hazard  
Safety gears required  to enter and work in the facility  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 MEDC 02 (1901) DTZS  
24  ©TBS 2023 – All rights res erved  
 Annex A  
(Normative)  
Routine Inspection Checks  
 
The following routine checks should be carried out  during the service life of the Structure : 
 
a) Main structure  
i. Check that there are no structure components missing  
ii. Check that bars are neither warped, holed nor spitted and replaces  all defective parts.  
iii. Check structure components for corrosion  
iv. Check that draining holes on pipe leg memb ers, pipe lattice parts are not blocked.  
v. Check the climbing facilities, platforms, catwalks for integrity  
 
b) Tower Base Foundation  
i. Check for settlements or movements  
ii. Check for erosion  
iii. Check general site condition (standing water, drainage, trees etc.)  
iv. Check bolts, nuts and lock nuts for ti ghtness  
v. Grout condition  
 
c) Guy wires  
i. Check that each cable that is part of the  guy wire is neither broken nor warped  
ii. Measure the tension of each guy wire  using a strand dynamometer and compare result 
with the installer's stated values.  
iii. Check guy wires condit ion (corrosion, breaks, nicks, kinks, etc)  
iv. Check that the guy wire tightening system is properly greased.  
v. Check for loose or missing fasteners  
vi. Check base for settlement, movement or earth cracks  
vii. Check backfill heaped over concrete for water shedding  
viii. Check anchor rod condition below earth  
ix. Check for signs of corrosion and take remedial timely steps  
x. Ensure anchor head is clear of earth  
 
d) Bolting parts  
i. Check that no bolts or nuts or any bolting part like washers, pins, etc is missing. Replace 
these immediately.  
ii. Check bolts tightening.  
iii. Check bolts, nuts and bolting parts for corrosion.  
iv. Check anchorage rod in the concrete.  
 
e) Verticality  
i. Check with the appropriate devices such a s theodolite that the structure stands in a 
vertical position.  
ii. There shall be no tilts. Ta ke two measu rements in two different planes with a 90' angle 
difference.  
 
f) Antennas and Accessories  
i. Check antennas and antenna supports  
ii. Check coaxial cables  
iii. Check fixing clamps.  
 
g) Safety components  
i. Check that access ladder is in good condition  MEDC 02 (1901) DTZS  
25  ©TBS 2023 – All rights res erved  
 ii. Check rest and  work platforms for defects, wear and tear  
iii. Check that all safety components are existing and complete  
iv. Check the correct functioning of the fall arrestor system  
v. For a fall arrestor system with cable, ch eck that the cable has not been over tightened.  
vi. Check t hat the anti-climbing  door is functioning.  
 
h) Lightning and Earthing system  
i. Check that all lightning and Earth ing components are existing and complete including 
lightning arrestor, copper strip, connection plate,  
ii. Check the Earthing connection of coaxial cabl es, 
iii. Measure the resistivity of the Earth and  confirm conformity to expected values.  
 
i) Aviation Safety Lights  
i. Check that all components are in place,  
ii. Check condition and well-functioning  of components (Light bulb, energy  cables, fixing 
parts, photoelectric c ell, connections)  
iii. Check earthing of the light wiring.  
 
j) Anti-corrosion  protection  
i. Check all galvanized  members for integrity . 
ii. Check paint condition.  
iii. Check for signs of corrosion on the s tructure, of the bolts, bolting accessories, harnesses, 
antenna support s, etc . 
iv. For guyed masts, check for corrosion on the entire guy assembly.  
 
k) Salty environment  
i. Wash the structure and accessories with clean water once every six (6) months to 
eliminate residue salt pa rticles which may not be washed away by rain.  
 
l) Concrete bl ocks 
i. Check the good condition of above ground concrete block parts.  
ii. There must not be any water collection, cr acking or splitting, chipped or broken concrete.  
iii. Check the condition of anchor setting in the concrete block.  
iv. Check anchor -bolt corrosion.  
 
m) Tower loading  
i. Check types, numbers and installed heights of all antennas currently on the structure and 
confirm that the loading does not exceed structure design load  
 
 
 
 
 
 
 MEDC 02 (1901) DTZS  
26  ©TBS 2023 – All rights res erved  
 Annex B  
 
(Normative ) 
 
Preventive Maintenance  Inspection  Checks  
 
The following Preventive  Maintenance Che cks shall be carried out during the service life of the Structure.  
 
a) Structure  
i. Tension of Guy wires using a dynamometer.  
ii. Geometry of the structure.  
iii. Re-tighten main structure and accessories bolted parts (10%)  
iv. Geometry of the Bars.  
v. Rigidity o f Antennas and Accessories.  
 
b) Safety  
i. Ensure that anti climb door can open and close. Clean and grease all hinges.  
ii. Ensure the work platform's trap can open and close. Clean and grease all door hinges.  
iii. Check the fall arrestor system  
iv. Check tower ladder for any  signs of weakness, re -tighten all bolts  
v. Check the riggers’ safety gear, take inventory and record it  
vi. Check the positioning and installation of safety components.  
vii. Test the fall arrestor system with individual equipment.  
 
c) Earthing  
i. Check the physical conditi on of the lightning rod and lightning arrestor  
ii. Check the physical condition and installation of the copper strip  
iii. Check the connection of the concrete block copper belting  onto the copper strip the 
connection of coaxial cables earthing onto the copper strip 
iv. Check the connection between the bo ttom coaxial cable earthing and the collection 
Copper bar fixed on the concrete block  
v. Check the tightening of the brass bolts of  the lightning protection electrodes  
vi. Check the resistivity of the lightning protection elect rodes  
vii. Earth resistance  
 
d) Aviation Safety Lights  
The following checks should be carried out:  
i. Functionality of controllers, flashers, alarms and photo control  
ii. Condition of electrical wires, connectors and earthing  
iii. Condition and fixing of energy cables  
iv. Conduit , junction boxes, and fasteners weather tight and secure  
v. Bulb condition - change all bulbs at t he same time immediately before the rated service 
hours is achieved.  
vi. Condition and fidel ity of the power supply systems  
 
e) Coating  
i. To prevent discrepancies in galv anization  
ii. Paint coating. Repaint every three years  
iii. Rust and/or corrosion conditions  
iv. ICAO / TCAA  Colour marking conditions  
v. Water collection in members - unplug drain holes, etc.  
 
 
 MEDC 02 (1901) DTZS  
27  ©TBS 2023 – All rights res erved  
 f) Records  
i. A record keeping method  shall be maintained in wh ich all maintenance  checks made will 
be documented.  
ii. The contents of the records  shall in clude: date of checks, what was checked, 
observations of the check , and name and signature of the personnel that conducted the 
check.  
iii. The records  shall be made availab le to the regulator  or its due representative on 
demand.  
 
g) Tower Alignment  
Tower Plumb and Twist (See Figures 1 and 2 ) 
The transit is to be set up on each leg azimuth at the base of the tower. The corresponding tower  leg at 
the base of the tower is used to set the vertical bas eline. The deflection at each point of  interest on the 
tower is measured from this vertical baseline, as shown below.  
 
Figure 1: Twist and Out -of Plumb Determination for Triangular Towers  MEDC 02 (1901) DTZS  
28  ©TBS 2023 – All rights res erved  
  
The transit is to be set up on each leg azimut h at the base of the tower. The corresponding tower  leg at 
the base of the tower is used to set the vertical baseline. The deflection at each point of  interest on the 
tower is measured from this vertical baseline, as shown below.  
 
 
Figure 2: Twist and Out -of-Plumb Determination for Square Towers  
 
 
 
 
 
 MEDC 02 (1901) DTZS  
29  ©TBS 2023 – All rights res erved  
 Bibliograph  
AS 3995 —1994, Design of steel lattice towers and masts, published by the Standards Australia 
(Stan dards Association of Australia) . 
 
ANSI/TIA -222-H-2017 , Structural Standard for Antenna Supporting Structures and Antennas and Small 
Wind Turbine support structures  published by the Telecommunications Industry Association  in 
association with American National Standards Institute . 
 
TANESCO Distribution Engineering Instruction Manual , 9th Edition.  
ICNIRP Publication – 2020 , ICNIRP Guidelines for Limiting Exposure to Electromagnetic Fields (100 KHZ 
to 300 GHZ)  
ICAO Doc 9157 Aerodrome Design Manual Part 4 — Visual Aids, Fifth Edition, 2021  
ICAO Doc 913 7 Airport Services Manual Part 6 — Control of Obstacles , Second  Edition, 1983  
TCAA/QSP/SR/AC/AGA -01 Advisory circular on control of obstacles  
TCAA/QSP/SR/AC/AGA -016 Advisory circular on land use and environmental management in the vicinity 
of aerodromes  
TCAA/QSP/SR/AC/AGA -028 Advisory circular on processing aero nautical permits of tall structures  
TCAA/QSP/SR/AC/AGA -033 Advisory circular on guidance on lighting and marking of obstacles