Retractable Earthing Device (RED®) which is used for FRT roof and shell bonding protects these tanks against damages resulted from lightning and the aggregation of electrostatic charges. RED® is responsible for making a connection with perfect electrical continuity between tank roof and shell . This retractable earthing device is installed on the shell of tank and the end of its strap conductor is connected to tank roof and the length of conductor increases and decreases with the movement of tank roof. Therefore, the length of conductor is the lowest at any moment and as well as not preventing from the performance of tank floating roof, it will have the least electrical resistance (DC).  

Considering the installation of so many shunts one a tank, it is expected that a part of current wave with short front time and high wave amplitude is transferred to earth through shunts. However, another part of current with lower amplitude and longer length of time looks for a path with the least resistance to be transferred to earth through Bypass Conductor. So a suitable boning system has to be selected considering such items.  

Since the main reason of sparking is electric potential difference between roof and shell of tank, bonding components between these two is correctly and standardly considered to make a path with low resistance for transition of lightning and discharge of electrostatic charges and this is always studied, researched and investigated to improve the level of safety and protect tanks against damages resulted from lightning.  

Protecting FRT has become an important issue during recent years. As well as observing safety tips on the construction of tanks according to related standards-like API which has been exclusively written on the protection of tanks against lightning-another bonding has been considered through equipment called Bypass Conductor beside making boding through Shunts during these years to protect FRTs which makes electric connection between roof and  shell of tank.

Therefore, and considering the need of our country to tanks roof and shell bonding device or Bypass Conductor, using knowledge and power of Iranian engineers and craftsmen and after passing research and reverse engineering stages, Espak Co has succeeded to localize and optimize FRT boding device inside country. This device has been manufactured inside Iran according to the necessities of API and NFPA standards and has been patented as RED®.