See regs under 1.401(a)(9)
A charity has no life expectancy therefore cannot be considered a designated beneficiary for life expectancy determination. If more than one beneficiary is named and the shares are not segregated, then the account is treated as not having a beneficiary for life expectancy determination purposes and the life expectancy of the participant/account owner in the year of death is the L.E. used for determining the distribution period after death. See below
4.3 Q-3. May a person other than an individual be considered to be a designated beneficiary for purposes of section 401(a)(9)?
A-3. No, only individuals may be designated beneficiaries for purposes of section 401(a)(9). A person that is not an individual, such as the employee's estate, may not be a designated beneficiary.[96] If a person other than an individual is designated as a beneficiary of an employee's benefit, the employee will be treated as having no designated beneficiary for purposes of section 401(a)(9), even if there are also individuals designated as beneficiaries. However, see A-5 of this section for special rules that apply to trusts and A-2 and A-3 of §1.401(a)(9)-8 for rules that apply to separate accounts.[97]
RMD REGSScroll down a bit after going to link.