Types Of Airtight Access Covers And Their Uses

In keeping with global trends, the Indian market for manhole covers and access covers is also growing at a healthy pace. Leading foundries in India are gearing up to meet the surging demand levels, by constantly expanding their portfolio with high-quality, precision-engineered products. In particular, different varieties of gas and watertight access covers are being designed – giving buyers plenty of options to find and select the ‘right’ product for their precise requirements. Over here, we will look at some popular types of access covers and their applications:

Ductile Iron / Cast Iron Access Covers

This variety of access covers rank the highest in terms of strength, reliability and longevity. Comparatively, the ductile iron covers have greater mechanical strength than their cast iron counterparts. The corrosion-free assurance of these access covers is a major advantage, they are available in different load ratings (up to 400 kN testing load can be supported), and maintenance requirements are minimal. Ductile iron covers designed by the top manufacturers adhere to the BS EN 124:2015 standards. 

Ductile iron and cast iron access covers are particularly suitable for roadways with high vehicular traffic volumes. These covers are commonly used at airports as well.

Recessed Access Covers

Generally designed with customisations, recessed access covers (or, screed covers) are also popular. These special covers rank high on the durability count – and offer a combination of strength & functionality, and aesthetic appeal. Like other varieties, these access covers are also manufactured with premium-grade material.

Recessed access covers are mostly set up in driveways – thanks to their decorative value. In select neighbourhoods, these covers add excellent utility.

Solid Top Airtight Access Covers

The leading manufacturers and suppliers of gas and airtight access covers offer solid top covers of different varieties. These include single-part and two-part models, along with the multi-part variety (fitted with support beams). The covers generally have powerful grab handles, and are relatively lightweight in nature. Thanks to their smooth finishes, rust-free assurance, and secure fittings – the solid top covers offer high stability and safety levels. The choice of covers typically depends on the location / application where it will be used.

Solid top access covers are chosen for usage in areas where the loads are relatively lighter. Regular maintenance is required, to rule out possibilities of accidental damages and resultant problems. They are commonly installed in pavements, walkways and taxiways. 

Note: Access covers with concrete infill are also available. These varieties are the same as those of solid top covers.

Low-leakage Covers; Dust-proof Covers; Fire-rated Covers

These are special types of access covers that are customisable – and are designed to meet the specific requirements of the surroundings. Since these access covers are generally pre-primed and welded, there are no leakage risks, while there are models available with different fire ratings as well. Various frame options (e.g., flanged or feathered) are designed by the manufacturers – while buyers can also choose from products of multiple sizes / dimensions.

These covers are often chosen for installation at construction sites, heavy mining areas, and (in certain cases) at dockyards. The specification of the covers determine the precise use to which they can be put.

Note: While their strength is not as high as that of cast iron access covers, the removable carbon-steel manhole covers also find usage in a wide range of environments.

Classification Of Access Covers According To Weight Classes

Access covers, designed for residential, commercial and industrial areas, are also classified under various heads – on the basis of their load ratings. This load rating / weight – based categorisation is as under:

→ Access covers with A15 rating are used for pedestrian areas. 

→ For light traffic localities / driveaways, access covers in the B125 load class are chosen.

→ Covers with C250 and D400 load ratings are suitable for areas with slow-moving and fast-moving (heavier) vehicles.

→ In dockyards, warehouses and similar heavy-duty areas, E600-rated access covers are generally used.

→ F900 is the highest load rating for access covers. These are the go-to options for airports and such other places.

Why Choose Gas and Watertight Access Covers?

Access covers are subjected to harsh external conditions on a continuous basis. It is of paramount importance to choose products that can withstand these conditions – without undergoing significant damages, wear & tear, and other mechanical fatigue symptoms. Gas and watertight covers deliver great value on that count:

• Airtight access covers provide a safeguard against bacterial growth on the surfaces. As such, hygiene levels are maintained – and the long-term performance of the covers is not compromised in any way either.
• These covers also double up as effective barriers to moisture damages and dust-accumulation (which can lead to blockages).
• Risks of corrosion damage are minimal (if any), and frequent repairs or replacements are not required. The thermal efficiency of these covers is high, with the air permeability being maintained at very low levels. The top manufacturers also ensure quality-optimisation at every step – through rigorous checks and product inspections.

The cast iron products sector in general, and the manhole covers / access covers industry in particular, has been projected to grow at a robust CAGR over the next few years. The top cast iron manufacturer companies are continuously raising the quality as well as the range of their product portfolios. This trend will gain further momentum in the foreseeable future – and the onus lies on buyers (from different sectors) to have complete knowledge about the access covers available, and make an informed purchase decision.