Within 10-15 minutes, the AirRepair seal stopped the air leaks and limited further cracking. This repair has better results and performance than tape and putty used in the past. The high-strength AirRepair seal lends stability to the cable so it can withstand vibration and movement\u2014even footsteps.
\nAirRepair cures to a durable material that flexes and moves with the cable. The seal holds 10 psi (690mb) and is resistant to water, salt, oils, and other manhole contaminants.
\nEach pack contains enough material to seal one leak and can be spread along seams, around the body of the cable, or in the crotch joint of a splice. AirRepair seals leaks at a fraction of the cost of cable replacement, leading as an economical, high-performance solution for infrastructure maintenance.<\/p>\n"}],"graphic":{"image":{"ID":17584,"id":17584,"title":"Footer","filename":"Footer-1.jpg","filesize":154005,"url":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1.jpg","link":"https:\/\/www.polywater.com\/en\/solution-story\/airrepair-leads-the-way\/footer-2\/","alt":"preparation and repair of a lead-sheathed cable","author":"7","description":"","caption":"","name":"footer-2","status":"inherit","uploaded_to":17200,"date":"2022-08-31 19:36:38","modified":"2022-08-31 19:36:58","menu_order":0,"mime_type":"image\/jpeg","type":"image","subtype":"jpeg","icon":"https:\/\/www.polywater.com\/wp-includes\/images\/media\/default.png","width":1200,"height":383,"sizes":{"thumbnail":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1-150x150.jpg","thumbnail-width":150,"thumbnail-height":150,"medium":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1-300x96.jpg","medium-width":300,"medium-height":96,"medium_large":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1-768x245.jpg","medium_large-width":768,"medium_large-height":245,"large":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1-1024x327.jpg","large-width":1024,"large-height":327,"1536x1536":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1.jpg","1536x1536-width":1200,"1536x1536-height":383,"2048x2048":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1.jpg","2048x2048-width":1200,"2048x2048-height":383,"gform-image-choice-sm":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1.jpg","gform-image-choice-sm-width":300,"gform-image-choice-sm-height":96,"gform-image-choice-md":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1.jpg","gform-image-choice-md-width":400,"gform-image-choice-md-height":128,"gform-image-choice-lg":"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/08\/Footer-1.jpg","gform-image-choice-lg-width":600,"gform-image-choice-lg-height":192}},"position":"12"},"related_articles_mode":"manual","select_related_articles":[{"post_identity":{"ID":16759,"post_author":"7","post_date":"2022-08-26 19:10:05","post_date_gmt":"2022-08-27 00:10:05","post_content":"Serious manhole events, which can result in smoke, fire, and explosions, have been gaining more attention in recent years as the nation\u2019s infrastructure ages. Potential consequences include fatalities, physical injuries, damage to property, and roadway accidents. A variety of causes can lead to these events, and utility engineers continually offer solutions with various degrees of success. In the interview below, Stuart Hanebuth, noted expert on manhole events and public safety, describes the challenges of mitigating these events.\r\n
Q. How often do manhole events occur annually?<\/strong><\/h2>\r\nA.<\/strong> We don\u2019t know for sure how many underground structures there are in the U.S., but I estimate probably between one and two million. Based on what has been reported in the media and by utilities, I would estimate that nationwide there probably are between three and five thousand serious events per year that involve fires, explosions, or smoking manholes.\r\n\r\n![\"A](\"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/05\/Chicago-Sunday-Tribune-photo-500p.png\")
\r\nQ. Are manhole explosions a new phenomenon?<\/strong><\/h2>\r\nA.<\/strong> This newspaper clipping is from 1937. A manhole cover blew off and killed someone as it fell down an elevator shaft. It\u2019s one of the earliest manhole events that we can find, evidence that these events have been around for a very long time.\r\nQ. Could you please describe the main types of manhole events?<\/strong><\/h2>\r\nA.<\/strong> There are three broad categories of manhole events that are related to each other: smoking manholes, manhole fires, and manhole explosions. The most common type of event is a smoking manhole where a lot of smoke is coming out of an underground structure, but there is no fire or explosion visible at the surface.\r\n\r\nBy the way, when I say manhole, I mean any underground electrical structure with cables. It could be a vault, a service box, or any number of structures but it must be an underground structure. I use the term manhole for simplicity.\r\nQ. What are the typical causes of manhole events and the concerns surrounding each?<\/strong><\/h2>\r\nA.<\/strong> All manhole events are sourced by two types of energy, combustion driven and electrically driven. Combustion-driven events are most often the result of anaerobic decomposition from the smoldering cable insulation. Electrically driven events result in a large arc with very high temperature. Each type requires a different prevention method.\r\n\r\nOne example of an combustion-driven manhole event is <\/span>pi<\/span>ctured below. <\/span>Firetrucks <\/span>at the ready <\/span>can be seen in the background, as <\/span>t<\/span>he smoke and gases coming out of the <\/span>structure <\/span>\u00a0<\/span>may<\/span> become<\/span> a significant fire.<\/span> <\/span>\u00a0<\/span>\r\n\r\n![\"\"](\"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/06\/smoking-manhole-w-firetrucks.png\")
\r\n\r\nIn electrically driven events, energy for the event comes from an electrical fault inside the structure, typically an underground cable. Most electrically driven events happen on transmission and medium-voltage cable.\r\n\r\nA great example of an electrically driven\u00a0 event occurred in Buffalo, New York, several years ago and was caught on air during a news interview (video courtesy of WGRZ News<\/a>). An underground cable fault resulted in an arc that superheated the air and blew the cover five stories off the ground.\r\n\r\nThese types of explosions are incredibly energetic events. It\u2019s not uncommon to see covers blown many, many stories into the air. Incredibly, the cover did not hit anyone. But a 100-pound piece of metal flying into a person would result in a very serious accident. Besides physical injury and fatalities, these events can cause significant damage to property, roads, and other infrastructure. Finding effective ways to mitigate these types of events is very important.\r\n
Q. Could you please describe the main types of manhole events?<\/strong><\/h2>\r\nA.<\/strong> There are three broad categories of manhole events that are related to each other: smoking manholes, manhole fires, and manhole explosions. The most common type of event is a smoking manhole where a lot of smoke is coming out of an underground structure, but there is no fire or explosion visible at the surface.\r\n\r\nBy the way, when I say manhole, I mean any underground electrical structure with cables. It could be a vault, a service box, or any number of structures but it must be an underground structure. I use the term manhole for simplicity.\r\nQ. What are the typical causes of manhole events and the concerns surrounding each?<\/strong><\/h2>\r\nA.<\/strong> All manhole events are sourced by two types of energy, combustion driven and electrically driven. Combustion-driven events are most often the result of anaerobic decomposition from the smoldering cable insulation. Electrically driven events result in a large arc with very high temperature. Each type requires a different prevention method.\r\n\r\nOne example of an combustion-driven manhole event is <\/span>pi<\/span>ctured below. <\/span>Firetrucks <\/span>at the ready <\/span>can be seen in the background, as <\/span>t<\/span>he smoke and gases coming out of the <\/span>structure <\/span>\u00a0<\/span>may<\/span> become<\/span> a significant fire.<\/span> <\/span>\u00a0<\/span>\r\n\r\n\r\n\r\nIn electrically driven events, energy for the event comes from an electrical fault inside the structure, typically an underground cable. Most electrically driven events happen on transmission and medium-voltage cable.\r\n\r\nA great example of an electrically driven\u00a0 event occurred in Buffalo, New York, several years ago and was caught on air during a news interview (video courtesy of WGRZ News<\/a>). An underground cable fault resulted in an arc that superheated the air and blew the cover five stories off the ground.\r\n\r\nThese types of explosions are incredibly energetic events. It\u2019s not uncommon to see covers blown many, many stories into the air. Incredibly, the cover did not hit anyone. But a 100-pound piece of metal flying into a person would result in a very serious accident. Besides physical injury and fatalities, these events can cause significant damage to property, roads, and other infrastructure. Finding effective ways to mitigate these types of events is very important.\r\n
\r\n\r\nIn electrically driven events, energy for the event comes from an electrical fault inside the structure, typically an underground cable. Most electrically driven events happen on transmission and medium-voltage cable.\r\n\r\nA great example of an electrically driven\u00a0 event occurred in Buffalo, New York, several years ago and was caught on air during a news interview (video courtesy of WGRZ News<\/a>). An underground cable fault resulted in an arc that superheated the air and blew the cover five stories off the ground.\r\n\r\nThese types of explosions are incredibly energetic events. It\u2019s not uncommon to see covers blown many, many stories into the air. Incredibly, the cover did not hit anyone. But a 100-pound piece of metal flying into a person would result in a very serious accident. Besides physical injury and fatalities, these events can cause significant damage to property, roads, and other infrastructure. Finding effective ways to mitigate these types of events is very important.\r\n![\"A](\"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/06\/Figure-3-Diagram-800p-x-340p-1024x435.jpg\")
\r\nFIGURE 1<\/strong>\r\n\r\nMost of what is burning and causing fires and explosions is carbon monoxide. The hydrogen escapes through the cracks and pores in the ducts so it\u2019s pretty inconsequential. The duct decomposition process also leaves behind almost pure carbon dust. So, there is carbon dust, carbon monoxide gas, some hydrogen, and other things coming out right at the flame front, the reaction zone. Those gases must go someplace so they are flowing to the low-pressure end of the system, in other words, the manhole cover. You need airflow on the order of about 0.2 meters per second to support this process. At that rate, the airflow will force the flame front along the cable and duct material where it will continue to create large amounts of gas.\r\n\r\nIt is important to note that you must have the airflow. Without it, the reaction zone or the flame front cannot be moved down the cable. The gas has no place to go, and the fire essentially self-extinguishes. There will be arcing, and it may progress into an electrically driven event, but an electrically driven event inside of a duct is much less severe than a combustion-driven event occurring in a manhole.\r\n![\"Testing](\"https:\/\/www.polywater.com\/wp-content\/uploads\/2022\/06\/Testing-Manhole-cover-explosion-600p-x-400p.png\")
\r\n