Test equipment

Mettler Toledo T70 with automated sampler

Sample size

30ml (recommended), 10ml (minimum)


ASTM D4739



Test methodology

BN is determined by the amount of hydrochloric acid (HCl) required to neutralize the base in one gram of an oil sample.

Notes (application)

Base number (BN) test measures reserve alkalinity of a lubricant. This alkalinity reserve is needed within the oil to neutralise acidic by-products within the oil that accumulates during in-service conditions.

By measuring the BN, we are capable to determine if the lubricant have sufficient amount of additives to resist oxidation by the acid formed. Acidic oils contribute to corrosion of engine components, among other issues.

Suitable for systems

Engine oils (Ie. diesel engines, gas engines)