Choosing a manhole cover might seem like an easy task, but it is crucial to pick the right one that suits your purpose or application. Before deciding, one must consider various factors because a maintenance hole cover is a versatile object whose proper function is imperative for society or the state. Any wrong decision may lead to situations like tank damage, environmental hazards, or sudden leakages! Bad choices are generally a threat to the safety of your operators as well. It is crucial to make an intelligent choice before investing in a manhole cover. I will help you in attaining the right manhole cover for storage tanks in 2021.
The Chemical Being Stored
One of the most rampant uses of manhole covers is in different chemical and pharmaceutical industries. But even besides these industries, various chemicals are constantly in use by the manways. And the first thing one needs to consider is what chemical is in the storage tank. Keep in mind that this is the most consistent factor in determining what manway cover would suit your application.
The reason is some chemicals are more toxic than others and need some specifically designed systems. For example, suppose it is a water storage tank. In that case, the manufacturers have to focus on the safety element first and avoid using a corrosive or harmful chemical, like hydrochloric acid (HCl). Special corrosion-resistant tanks and covers prevent fumes from escaping into the air for such toxic and highly caustic chemicals. The HCL storage tanks usually have air-tight utility hole covers to allow the scrubber to work correctly.
Take another example of hydrogen peroxide, which is known to decompose rapidly. Such chemicals or hydrogen peroxide tanks need to have a hinged-weighted manway cover. The hinged-weighted maintenance hole covers avert the pressure build-up from disintegration.
How the Tank Is Filled
The following vital thing to keep in mind before picking a manhole cover is filling the storage tank. The three different ways of filling chemical storage tanks are filling via a mechanical pump, filling through gravity, and a Pneumatic fill. Storage tanks served Pneumatically are under a lot of pressure because, in this technique, the chemical blows inside the storage tanks.
For such pressure circumstances, storage tank systems fit safety devices like Poly Processing’s SAFE-Surge® utility hole cover or the FS 2650 cover. Initially designed for emergency pressure relief, it eructs at about 0.8 PSI and then shuts down after pressure release. Chemicals giving off vapors are not on their usable list.
On the other hand, the FS 2650 is a venting cover. This distinctive manhole cover has a mushroom head. The venting is possible after the manufacturers drill some holes under this mushroom head. The mushroom head of the FS 2650 prevents any debris or even rainwater from entering the storage tank. These maintenance hole covers are only used for non-fuming chemicals and can discharge a volume flow rate of up to 2650 ACFM.
Furthermore, storage tanks not filled via the Pneumatic technique, such as sulfuric acid, need to eliminate exposure. For elimination, a bolted manway cover seals off the storage tank.
Type of Access Required
The third point to consider is how you are going to access that chemical storage tank. The type of access needed would have an impact on the manhole cover as well. For example, due to the acid’s corrosive nature, HCL, a fume-tight manhole cover, is obligatory for protecting the surrounding, including the equipment around, the people everywhere, and the environment. On the contrary, a threaded manhole cover works well for the water storage tanks as water is not toxic. The storage tank can easily be treated regularly and drained from time to time.
The Perfect Size
Size is another most essential thing to consider when choosing the manhole covers. They must fit into the tanks, or else it could lead to different issues and hazards. Thankfully, there is a precise way to check if the manhole cover has been adjusted in the storage tank aptly. First, you need to measure the inside dimensions of the tank. Subsequently, measure the size of the manhole cover as well in millimeters for precise results. Other manufacturers already list different measurements. Anyone can easily browse the internet that would also show you which size is suited for which application. Eventually, this is how you can find the perfect fit of manhole cover for your project.
The most common square and rectangular manhole cover sizes usually come in the ranges of 300mm x 300mm to 1200mm x 1200mm. On the other hand, the most popular Circular manhole covers are 450mm and 600mm diameters.
The Right Manway Cover for Your System
The manholes cover has various pressure levels, shapes, sizes, and elements. One has to look upon all these factors before making the right choice for an effective and safe tank system. Any wrong choice could lead to any unfavorable circumstances for the people, environment, or equipment. The suitable tank manhole covers are the only one that suits the requirement of the application. Finding a relaible manufacturer of such covers as LikeMetals is hard. One must first check all the parameters before trading with new supplier of manhole covers.
