The strength, durability and versatility of nickel-containing stainless steels ensure that this powerful metal has a vast array of applications, none of which is more important than saving lives.
In 2009, a toddler in Auckland, New Zealand, was lost from home. A week later, the two-year-old child was found dead in the underground drainage system, which was accessed through the manhole cover, which was opened by the recent storm.
The scourge disrupted the local builder and the father of two children, Kevin Maskell, who felt that something must be done to prevent the baby from slipping out of the manhole again.
Maskell has spent a lot of time on this, he said, "When I woke up one morning, I had a solution in my mind."
In fact, this solution is surprisingly simple: this is to design a safety grill that can be bolted easily under the manhole cover. Maskell's design does not impede the integrity of the closed manhole and poses no threat to drivers or pedestrians. What's more, it takes less than a minute to remove and install the grille without letting the scent escape.
Maskell hired an engineer to make a sample and then patented it, calling his invention "Caliber Safety Grill."
This circular device is welded with 8mm steel bars at the center of 150mm. In order to obtain the desired service life, low carbon steel hot dip galvanized steel is generally used, and 304 stainless steel (S30400) grid can also be used. If it is a corrosive environment such as coastal areas or where there may be acidic water or corrosive wastewater, 316 (UNS S31600) nickel-containing stainless steel should be used.
The advantages of stainless steel include high strength, durability, low maintenance and ease of use. And all three materials can be retrofitted to new and existing manhole covers without being affected by their specifications.
In fact, thousands of drains require a safety grille, so this easy-to-install and low-maintenance unit is a huge attraction for the council. The installation of stainless steel safety grille has become part of the main safety plan for Auckland City Council, New Zealand's largest city.