GENERAL INFO
You can choose the proper CML pali lighting towers related to the proper wind zones, which can be classified as follows:
- Lighting towers with fixed platform, TP series with ladder, possible fall protection guardrail or other protection for the operator climbing to heights
- Lighting towers with mobile trolley, TM series, with lifting/lowering system of the sliding spotlight holder structure
- Lighting towers with mobile crown, TC series, with lifting/lowering system of the crown supporting the reflectors.
The TP series lighting towers can be recommended for installations where suitable personnel are available to carry out high-altitude maintenance of reflectors and accessories. The TM and TC series lighting towers can be recommended for installations where maintenance of the reflectors and their accessories is carried out on the ground.
The features needed to identify the proper lighting tower for a specific lighting system are the following:
Height above ground of the installation point of the floodlights
It is the height measured from the lighting plane to the central point of the projector in question: if the projectors will be installed in two overlapping rows it is advisable to evaluate the average height. The required height must be rounded to the upper standard height of the pole.
Quantity, dimensions and features of floodlights
It is necessary to have precise data relating to the quantity, unit surface area exposed to the wind, unit weight, brand and model of the floodlights to make choices about the type of tower needed.
With this data you can:
- calculate the total surface of the floodlights exposed to the wind
- check the suitability of brackets and accessories to allow the installation of the floodlights
Positioning the floodlights
The floodlights must illuminate a previously defined area in the lighting project: consequently, they can be arranged:
- at 360° - to evenly illuminate the tower surrounding area
- at 180° - per illuminare solo una parte dell’area
circostante la torre - according to specific scheme – to illuminate a well determined sector
Their positioning affects the calculation of the total equivalent surface exposed to the wind (see below).
Type of installation
The light tower must be installed on a concrete foundation block of adequate dimensions calculated / verified according to the ground features. The foundation block can feature:
- a hole of suitable diameter and depth to house the initial part of the tower stem (direct insertion)
- anchor bolts embedded in the concrete to fix the tower's base plate.
Wind zones and conditions of chosen area to install CML lighting towers
This data is needed to determine the forces acting on the CML columns and floodlights and, consequently, identify the performance of the columns based on wind zones. The calculation of the windiness (Vref) is carried out by applying the parameters indicated by the Eurocode UNI ENV 1991-2-4 standard reported in the Ministerial Decree 16/1/96 Technical standards relating to the general criteria for the safety verification of constructions and loads and overloads and by the Circular of the Ministry of Public Works n° 156.AA.GG/STC.
NOTE: TO MAKE THE CHOICE, THE INSTALLATION PLACE OF THE CML LIGHTING TOWERS MUST BE CLEARLY DEFINED; THE MUNICIPALITY AND PROVINCE OF THE INSTALLATION LOCATION AND THE ALTITUDE OF THE INSTALLATION PLACE MUST BE SPECIFIED.
Possible mounting of a dome (only for the TM and TC series light towers)
For “TM” series tower models (towers with mobile trolley) and “TC” series (towers with mobile crown) a dome can be installed above the reflectors to reduce/eliminate light pollution at altitude: the dome is normally made of modular elements mounted above the top structure.
Lifting system (only for TM and TC series light towers)
The “TM” series tower models (towers with mobile trolley) and “TC” series (towers with mobile crown) can be equipped with various types of lifting systems (check compatibility with each type of tower.).
Floodlights: calculation of the surface exposed to the wind
Below are the formulas (in simplified mode) for calculating the overall surface area exposed to the wind based on projectors features.
S = N x SR x 0,6
S = N x SR x 0,8
NOTE: WHEN THE FLOODLIGHTS ARE ARRANGED DIFFERENTLY FROM WHAT SHOWN IN B1 AND B2, THEN TOTAL SURFACE MUST BE CALCULATED ANALYTICALLY
P = N x PR
DOME: surface exposed to the wind
The surface exposed to the wind of the standard dome models produced by CML pali have the following features:
Table for calculating the wind exposure category
TERRAIN ROUGHNESS CLASS
Terrain category
A Urban areas where at least 15% of the surface is covered with buildings with an average height greater than 15 m.
Installation areas
Zone 1
+1K slm Vref, 0: 25 m/s (0,012)
Valle d’Aosta, Piemonte, Lombardia, Trentino Alto Adige, Veneto, Friuli Venezia Giulia
Zone 2
+750 slm Vref, 0: 25 m/s (0,024)
Emilia Romagna
Zone 3
+500 slm Vref, 0: 27 m/s (0,030)
Toscana, Marche, Umbria, Lazio, Abruzzo, Molise, Campania, Puglia, Basilicata, Calabria
Zone 4
+500 slm Vref, 0: 28 m/s (0,030)
Sicily and province of Reggio Calabria
Zone 5
+750 slm Vref, 0: 28 m/s (0,024)
Sardinia (area to the east of the line connecting C. Teulada and La Maddalena Island)
Zone 6
+500 slm Vref, 0: 28 m/s (0,030)
Sardinia (area to the west of the line connecting C. Teulada and La Maddalena Island)
Zone 7
+1K slm Vref, 0: 28 m/s (0,024)
Liguria
Zone 8
+1.5K slm Vref, 0: 30 m/s (0,012)
Province of Trieste
Zone 9
+500 slm Vref, 0: 31 m/s (0,030)
Islands (with the exception of Sicily and Sardinia) and open sea
Vref = Vref, 0+(coefficient for each meter above the zone limit quota-M)
“M” = [ installation height in metres – limit altitude of the affected area ]
For installations at altitudes lower than the limit altitude Vref = Vref, 0
In RED: limit altitude of the affected area
In GREEN: Base reference wind speed
In YELLOW: coefficient for each meter above the zone limit quota
Brief summary of the operations to be carried out for choosing the proper CML lighting tower:
- Calculate the equivalent surface area of floodlights
- Calculate the total weight of floodlights and their accessories
- Survey: is mounting of the dome possible?
- Define total surface area (floodlights+dome) and total weight (floodlights+accessories)
- Identify the geographical area
- Identify the soil roughness category
- Define the exposure category
- Calculate Vref if installation is carried out at altitudes above sea level
- Partial compilation of the “TC series lighting tower request” form
- Research the performance of TC tower with height above ground Hft
- Calculate the equivalent virtual performance if installation is carried out at altitudes above sea level beyond the limits
- Search for tower's features
- Do I need any other equipment (power supply with 2-3 electrical cables, dome, multipurpose bracket, brackets for accessories, particular applications, signal lamp, particular external treatments, platform, etc.)?
- Final compilation of the “XX series lighting tower request” form
For further details:
Download the CML pali lighting tower selection catalog
Lighting tower performance table
- For each type of lighting tower, the performances (expressed as actual net m) of equipment that can be applied on the top are listed.
- Each table lists the performances calculated for each lighting tower type (direct insertion type or flange and anchored bolts) given the same height above ground.
- The acronyms identifying each lighting tower are composed as follows:
- The performance tables are made up of a basic table (for each type of tower); towers are listed from the least resistant model to the most resistant one and are organized as shown below.
The standard performance table of lighting towers is calculated for the Vref,0 of each mentioned area
The calculations of wind zones and all types of lighting towers described in this catalogue, with related design loads, were carried out in accordance with the following legislative provisions and/or reference standards:
- Law no. 1086 of 05/11/71: Norme per la disciplina delle opere di conglomerato cementizio armato, normale e precompresso ed a struttura metallica”.
- Ministerial Circular 02/02/09 n° 617: Istruzioni per l’applicazione delle norme tecniche per le costruzioni di cui D.M. 14 Genaio 2008.
- CNR - UNI 10011/88: Costruzioni in acciaio: istruzioni per il calcolo, l’esecuzione, il collaudo e la manutenzione.
- CNR – UNI 10022/84: Profilati di acciaio formati a freddo: Istruzioni per l’impiego nelle costruzioni.
Once calculations have been made, it is possible to proceed with the choice of the CML lighting tower using the form Scheda richiesta della torre faro, on the last page of the pdf catalog which can be downloaded at the following link:
Download the CML pali lighting tower selection catalog
Ref.: CML pali
