def R10_yield(FMTab, Apmin, PG):
    """
    R10 Determining the surface pressure Pmax
        (Sec 5.5.4)
    For the maximum surface pressure with yield
    or angle controlled tightening techniques.
    """
    
    #
    Pmax = 1.40 * (FMTab / Apmin)   # (R10/3)
    
    # Alternative safety verification
    Sp = PG / Pmax     # (R10/4)
    
    if Sp  > 1.0 : print('Sp > {} --> PASS'.format(Sp))
        
    else: print('Sp < {} --> FAIL'.format(Sp))    
    #
    return Pmax
    #