With time, the rules governing inspection of Gas Flues keep changing and a hidden flue requires Inspection Hatches to enable visual inspection throughout its length to be conducted when the servicing of the boiler is done. Wherever the flue changes its direction, it has to be visible from both the sides and all the joins are supposed to be within a space of 1.5 metres of the inspection hatch. These hatches are primarily of the following kinds- steel door inspection hatch, non fire rated metal, and plastic inspection hatch. You can also opt for the fitting of Inspection Hatches with locks, and these can be very useful for areas of community usage. A leakage in the Gas Flues can be hazardous and lead to Carbon Monoxide Poisoning. And therefore, it is important to get the inspections done at regular intervals and also treat the damages, if found, at the earliest.