When a sight window needs lighting
Signs that natural light is not enough and what to verify when choosing a light fitting.
Short answer
Lighting is needed when the medium is turbid, foams or the vessel is deep: observation without light becomes unreliable. Choosing a lamp means compatibility with the fitting body and the installation area.
Lighting does not increase the permissible pressure of the fitting and does not replace its calculation; lamp characteristics are confirmed by the lamp manufacturer.
Signs that lighting is necessary
- the medium is turbid, dark or foaming — light does not reach the observation zone;
- the vessel is deep: illumination falls with depth;
- colour or homogeneity control requires stable illumination;
- night shifts and enclosed spaces without daylight.
What to verify when choosing
A sight window lamp is usually mounted on the fitting body or nearby. Verify:
- compatibility with the body of the specific fitting (connection, diameter);
- permissible medium and temperature conditions of the lamp;
- a version for the Ex zone, if the zone exists;
- maintenance: replacing the light source without dismantling the fitting.
Limits
Lighting adds a penetration and maintenance work: verify leak-tightness and access. Brightness that dazzles the operator is as harmful as its lack.