There Is Nothing In The Nec About Egress Illumination Lighting Levels, However If You Look In The International Building Code In Means Of Egress Illumination, It Will State That That The Level Of Illumination Shall Be Not Less Than 1 Foot-candle (11 Lux) At The Walking Surface. There Are Exps. Depending What Your Municipality Has Adopted For Local Codes You Might Be Able To Use The Ibc. Somebody Will Have To Calculate The Amount Of Fixtures To Accomplish The Lighting Level. As An Electrical Inspector You Are Usually Responsible For The Installation ( Nec Code Compliance) Not The Actual Lighting Level. In My Area The Building Official Will Use A Light Meter To Check Levels.