Abstract: Fitting data points by spline curves is an important method of data processing. A typical
example of fitting with multi-constraints in project is presented. Gas explosion analysis is an important
issue related to production safety. Precise and safe explosive boundaries are helpful to hazard prediction
and control. This paper analyzes the experimental data obtained from the firefighting company, and
provides the explosion bounds and explosive strength based on multi-constrained spline fitting method.
Specifically, different characteristics of the gas explosion are converted to mathematical constraints and
then are simplified appropriately. Fitting B-spline curves to the data points under these conditions
results in the explosive strength curves with the explosive characteristics. This method can be
generalized to multi-factor explosion analysis, not restricted to dimensions.

Key words: B-spline fitting, multi-constraints, explosion bound, explosive strength