Streamer-Delaying Structural Lightning Protection
UNDERSTANDING THE LIGHTNING STRIkE CompLETIoN mECHANISm
Various mechanisms create a stratified charge in a storm cloud. The charge on the base of the cloud induces an opposite charge on the surface of the earth beneath it. As the storm cloud builds, it increases the potential difference between the cloud base charge and the ground charge, with the cloud base charge trying to pull the ground charge off the surface of the earth.
When the dielectric of the air is overcome and lightning is going to strike, the process begins with the formation of stepped leaders branching down from the cloud. These stepped leaders propagate in jumps of about one hundred and fifty feet at a time, towards the ground. These stepped leaders are the tendril-like branches extending down from the cloud which are visible in a photograph of a lightning strike. We see a lightning strike in two dimensions, but the field of stepped leaders is actually three dimensional.
When the stepped leaders are within five hundred feet or so of the ground, the electric field intensity on the ground becomes so strong that objects and structures on the ground begin to break down electrically and respond by shooting streamers up toward the stepped leaders. When a streamer connects with a stepped leader, the ionized path becomes the channel for the main lightning discharge, and a lightning strike occurs.
DELAYING FoRmATIoN oF STREAmERS
Change in streamer initiation time, is a concept describing the influence air terminals have on the formation of streamers. ∆T is the change in time, as compared to a conventional lightning rod, of the release of the streamer from a particular air terminal. ∆L is the change in length, or more importantly height, of the streamer, and is derived from ∆T. The earlier a streamer is emitted, the longer it is relatively, and the more of a head start it has over other streamers from the same area. Therefore it has a better chance of reaching the stepped leaders first, and completing the strike to the air terminal. Conversely, anair terminal that delays the formation of streamers, or exhibits a negative ∆T and ∆L, is less likely to complete the strike to itself.
STREAmER DELAYING TECHNoLoGY
Lightning Master Sreamer Delaying Air Terminal technology is based on the Point-Discharge Formula given below: The Lightning Master Streamer-delaying lightning protection system employs the basic conventional system with modified air terminals which are designed to reduce the incidence of direct strikes to the protected structure. All of the components used in this type of system are UL Listed, and the system is designed to meet UL 96A and NFPA 780.
About Lightning Master
Lightning Master is a full service, full spectrum static solutions and lightning and transient protection company serving the oil and gas and chemical industries since 1984. Our complete line of products and systems is backed by our worldwide support and customer service. Lightning Master has become recognized internationally as the industry leader in lightning and static protection. Unparalleled Customer Service · We’re with you every step of the way.
Site Survey and Evaluation:
• Our field engineers create a detailed report with the findings and recommendations on your site
• Our team of experienced engineers perform forensic analysis of lightning and static damage.
System Design
• We custom-tailor site-specific protection.
• We help you write specifications and best practices that meet your specific needs
Products
• Bonding and Grounding
• Surge Protective Devices
• Structural Lightning Protection
• LMC In-Tank Static Dissipators*
Customer Service
• Turn-key installation by Lightning Master-employed crews
• Training, supervision, and ongoing support of Customer personnel or
contractors
• Lightning Master approved installation contractors (in selected areas)
*PATENT PENDING
