Iron Covers Corrode Shut - Hammer Time!

Iron Cover Corrosion

Corrosion causes iron manhole covers to break

Corrosion in Wastewater and Grease Traps

Sewer Lids corrode from Hydrogen Sulfide gas exposure, water and salt, destroying the iron strength properties.   Improvements in stormwater infiltration prevention have made sewage less dilute, and H2S more concentrated.  Fats, Oils, and Grease (FOG) in grease traps also contribute to severe H2S production. H2S is converted to sulfuric acid by bacteria in the sewer system.

Corroded iron manhole covers show degradation

Corrosion Costs the US Infrastructure..."Big League"

"...the total annual estimated direct cost of corrosion in the U.S. is a staggering $276 billion"  Source: “Corrosion Costs and Preventive Strategies in the United States,” U.S. Federal Highway Administration (FHWA), PUBLICATION NO. FHWA-RD-01-156

Corroded manhole cover with holes and degraded

H-20 Strength...maybe new iron covers, but for how long?

Perhaps regulators should include H-20 / H-25 Proof Load re-certification by sampling existing covers at age intervals and institute scheduled replacement based on predicted corrosion rate with various PPM levels of H2S.  Otherwise, do we trust that current iron covers in-ground are safe?

Iron Corrosion Even Before Installation...Not CAP Covers!

Composite manhole covers and corroded iron manhole covers stacked next to each other

Degradation Due to Corrosion/Oxidation...Before Installation!

This photo shows stacks of CAP covers and iron covers at a local supply house.  The oxidation on the iron covers starts even before installation.  Some claim that this "patine" actually protects the covers, but experience shows that this far from enough.


It's Hammer Time!

Testimonial - Cracked Covers Are Left in the Streets

 One public utility supervisor recently admitted to CAP that workers sometimes crack covers during the hammering to dislodge them from the frame.  The operators feel they have done something wrong, and to avoid punishment, they would rather not tell anyone about the cracked cover and leave it in the street...waiting for the next unsuspecting driver or pedestrian!

Corrosion Fuses Covers Shut

Corrosion bonds the iron covers to the iron frames.  Municipal workers commonly slam the edges with a sledge-hammer or melt it with a flame torch to dislodge the cover from the frame.  This causes fracturing in the already corroded covers. Hydrogen Sulfide has riddled the cover with corrosion from the bottom, and the subsequent sledge-hammering from city workers finishes the job from the top.

Testimonial - Manholes with Fused Covers are Not Inspected

 A director for a wastewater collections department indicated to CAP that when he sends his operators out to do inspections that they will often skip inspecting the manholes that they cannot open without a hammer or flame torch.  That means that many of the manholes that probably need it the most do not get inspected!

Cracked Covers Can Break Causing Falls and Injury


Man Injured by Falling Through Cracked Cover -No One Takes Responsibility

" Brand received a letter from MSD explaining a crew went to the site and found a broken inlet cover, and replaced the cover. A second letter was sent from Corporate Claims Management Inc., which handles MSD’s liability claims. The company explained MSD had no prior notice of the condition of the manhole, therefore are unable to accept responsibility for injuries"

Corrosion Below The Cover - Frames

Corroded Frame Ledge - Floating Covers!

Cover About to Fall Due to Corroded Frame

Cover About to Fall Due to Corroded Frame

Corroded Frame Ledge - Manhole Covers without support

During a replacement, city workers observed that the cover support on the frame had entirely corroded away realizing why it was "sinking."

Cover About to Fall Due to Corroded Frame

Cover About to Fall Due to Corroded Frame

Cover About to Fall Due to Corroded Frame

Corroded manhole cover frame about to fall

Another cover in a Rio Grande Valley children's park scared local residents enough to photograph the incident and send to CAP.

Durability - Not Just UV Exposure!

Corrosion Affects the Frame and Concrete Below

Corrosion Affects the Frame and Concrete Below

Manhole cover durability above and below cover

Many inquire about the weather resistance while ignoring the more frequent reason for replacements - acid exposure under the cover.

Corrosion Affects the Frame and Concrete Below

Corrosion Affects the Frame and Concrete Below

Corrosion Affects the Frame and Concrete Below

manhole cover corrosion leaves its mark

Corrosion can get so aggressive that remnants of the oxidized iron are left on the concrete below the frame.

Manhole cover corrosion causes child to fall into Manhole

Corrosion Causes Child to Fall in Manhole

Hydrogen Sulfide Gas? No Problem for Composites!

Composites resist corrosion and acids

The material used in CAP's covers is also selected to use in frames and hangers in the electrowinning cathode/anode reaction.  In this copper purification process, copper sheets are held with composite supports inside a sulfuric acid tank.  While the acidic vapor eats through most materials, CAP materials resist the high concentrations of sulfuric acid vapor exposure.  

Durability-both sides of the cover? Just CAP that! ®